CN102760448B - The method of test magnetic head resistance to elevated temperatures and device thereof - Google Patents
The method of test magnetic head resistance to elevated temperatures and device thereof Download PDFInfo
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- CN102760448B CN102760448B CN201110109610.1A CN201110109610A CN102760448B CN 102760448 B CN102760448 B CN 102760448B CN 201110109610 A CN201110109610 A CN 201110109610A CN 102760448 B CN102760448 B CN 102760448B
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Abstract
The present invention discloses a kind of method testing magnetic head resistance to elevated temperatures, and described magnetic head includes air bearing face and two screen layers, and described method includes: applies the first magnetic field of multiple varying strengths with first direction to described magnetic head, and measures the first output parameter curve；Apply the second magnetic field of multiple varying strengths with second direction to described magnetic head, and measure the second output parameter curve；And judge whether described first output parameter curve and described second output parameter curve exist the change beyond feasible value, thus filter out bad magnetic head, wherein, described first direction is perpendicular to the air bearing face of described magnetic head, described second direction and described air bearing face are at an anglely through described air bearing face, and the absolute value of described angle is acute angle.The present invention can filter out the bad magnetic head with the best resistance to elevated temperatures in the case of not heating magnetic head accurately.
Description
Technical field
The present invention relates to a kind of method testing magnetic head performance, particularly relate to a kind of test magnetic head resistance to elevated temperatures
Method.And, the present invention relates to a kind of device testing magnetic head performance, particularly relate to a kind of test magnetic head
The device of resistance to elevated temperatures.
Background technology
The hard disk drive comprising multiple spinning disk is commonly used the magnetic storing data in its magnetic disk surface
Property medium on, and comprise read transducer removable magnetic head be used as from the track of magnetic disk surface read data.
Currently, magnetic resistance (magnetoresistive, MR) read head due to its be embedded with one more highly sensitive
MR element and be widely used in main flow magnetic head.Magnetic head is before use, it is necessary to carry out a series of performance test,
Such as resistance to elevated temperatures, dynamic fly height (dynamic flying height, DFH) performance, signal to noise ratio
(Signal-to-Noise Ratio, SNR) performance, reliability, stability etc..Such as, one has poor
The magnetic head of resistance to elevated temperatures, it can produce substantial amounts of noise in high temperature environments.If magnetic head has poor
SNR performance then can damage the read stability of magnetic head, finally affects the reading performance of magnetic head, therefore, magnetic head
Performance test seem particularly significant and necessary.
Following method is a kind of traditional method testing MR read head.As it is shown in figure 1, this MR read head 10 wraps
Include two Hard Magnetics 112, MR element 114 that layer is sandwiched between two Hard Magnetics 112 and be positioned over MR unit
Part 114 and two screen layers 1116 on Hard Magnetic 112 both sides.Known to all, the resistance of MR element can be with outside
The change in magnetic field and change, so that the output of MR read head produces change.Apply one have be parallel to screen
Cover layer 116 and the air bearing face 117 (air bearing surface, ABS) with MR read head 10 becomes 0 °
The magnetic field in direction 19 (hereinafter referred to as " the general direction of magnetization "), the output voltage of MR read head can be measured,
Repeat this kind of operation, then calculate the difference change between the highest output voltage and minimum output voltage,
This kind of difference change is used for estimating that exporting change is whether within a certain feasible value.If exporting change is in feasible value
Outside, then this tested magnetic head is judged as bad magnetic head and is rejected.More generally useful, in prior art often
Apply the magnetic field in a direction 18 being perpendicular to ABS 117, measure the output voltage of magnetic head, therefrom detect
The performance of magnetic head is the most qualified.
The general direction of magnetization of above-mentioned applying is widely used in magnetic head with the method for testing in the magnetic field being perpendicular to ABS
DFH performance test, SNR performance test and reliability and stability test.But, due to the property of magnetic head
Can require more and more higher, the most above-mentioned magnetized method of testing is restricted.Heat-resisting quantity as magnetic head
Can test, resistance to elevated temperatures is the most insensitive to the magnetization of this general direction of magnetization, therefore, and magnetic head
The method of resistance to elevated temperatures test is still in the middle of research.
The open No.20080049351A1 of United States Patent (USP) discloses a kind of method testing magnetic head resistance to elevated temperatures.
As in figure 2 it is shown, arrange a heating element heater 35 on the element formation surface 2101 of magnetic head 21, thus to magnetic
The MR element 32 of 21 applies heat and stress.Specifically, when energized, this heating element heater 35 generates heat,
In the case of this, MR element 32 and material generation thermal expansion about, so that MR element 32 produces greatly
The internal stress of amount is raw, additionally, MR element 32 is it also occur that internal modification.Thus, in the case, send out
Raw measured at the noise figure of the output of MR element 32, and then identify this tested magnetic head in hot environment
Lower can produce potential deformation thus produce noise.
But, due to magnetic head need to retest under the hot environment repeatedly changed, therefore the selection of temperature and
Control needs the most accurate.If temperature is the highest, then can exist test during by non-defective unit magnetic head damage can
Energy.
Again and, said method is only applicable to be embedded with the magnetic head of heating element heater, for not having the magnetic of heating element heater
Head then cannot use the method to carry out resistance to elevated temperatures test.
It would therefore be highly desirable to the method for the test magnetic head resistance to elevated temperatures of a kind of improvement, and test magnetic head performance
Method is to overcome drawbacks described above.
Summary of the invention
It is an object of the present invention to provide a kind of method testing magnetic head resistance to elevated temperatures, it can be not
The bad magnetic head with the best resistance to elevated temperatures is filtered out in the case of magnetic head is heated.
Further object is that a kind of method testing magnetic head performance of offer, it is capable of detecting when to adopt
The bad magnetic head that cannot detect completely by general magnetized traditional method.
It is yet a further object of the present invention to provide a kind of device testing magnetic head resistance to elevated temperatures, it can be
The bad magnetic head with the best resistance to elevated temperatures is filtered out in the case of magnetic head not being heated.
A further object of the present invention is to provide a kind of device testing magnetic head performance, and it is capable of detecting when to adopt
The bad magnetic head that cannot detect completely by general magnetized traditional method.
For reaching object above, the present invention provides a kind of method testing magnetic head resistance to elevated temperatures, described magnetic head
Including air bearing face and two screen layers, described method includes with first direction multiple not to the applying of described magnetic head
With the first magnetic field of intensity, and measure the first output parameter curve；Apply many with second direction to described magnetic head
Second magnetic field of individual varying strength, and measure the second output parameter curve；And judge described first output ginseng
Whether number curve and described second output parameter curve exist the change beyond feasible value, thus filters out not
Good magnetic head.Wherein, described first direction is perpendicular to the air bearing face of described magnetic head, described second direction with
Described air bearing face is at an anglely through described air bearing face, and the absolute value of described angle is acute angle.
As a preferred embodiment, the method also includes controlling described magnetic head so that described air bearing face
It is parallel to horizontal plane, then applies described second magnetic field to described magnetic head.
As another preferred embodiment, the method also includes controlling described magnetic head so that described air bearing face
With the horizontal described angle, then apply described second magnetic field to described magnetic head.
It is preferred that the scope of described angle is-20 °～20 °, wherein except 0 °.
It is preferred that described first direction and described second direction penetrate described air bearing face and/or from described sky
Air bearing section passes.
Alternatively, the method also includes applying the 3rd magnetic field, described third party with third direction to described magnetic head
To being parallel to described screen layer and becoming 0 ° of angle with described air bearing face.
It is preferred that the scope of the intensity in the intensity in described first magnetic field and described second magnetic field is
-800Oe～800Oe.
It is preferred that described first output parameter curve and described second output parameter curve are represented by output voltage.
Alternatively, described first output parameter curve and described second output parameter curve are represented by signal to noise ratio.
It is preferred that described change has a maximum transition, described maximum transition has transition rate, described appearance
The transition rate being permitted value is 8%.
The present invention provides a kind of method testing magnetic head performance, and described magnetic head includes air bearing face and two shieldings
Layer, described method includes applying the second magnetic field with second direction to described magnetic head, and measures the defeated of described magnetic head
Going out parameter, described second direction and described air bearing face are at an anglely through described air bearing face, institute
The absolute value stating angle is acute angle；And repeat to apply the second magnetic field of varying strength, and measurement repeatedly exports
Parameter, thus test the performance of described magnetic head.
As a preferred embodiment, the method also includes controlling described magnetic head so that described air bearing face
It is parallel to horizontal plane, then applies described second magnetic field to described magnetic head.
As another preferred embodiment, the method also includes controlling described magnetic head so that described air bearing face
With the horizontal described angle, then apply described second magnetic field to described magnetic head.
It is preferred that the scope of described angle is-20 °～20 °, wherein except 0 °.
It is preferred that described second direction penetrates described air bearing face and/or passes from described air bearing face.
Alternatively, the method also includes being perpendicular to the first direction in described air bearing face and executes to described magnetic head
Add the first magnetic field.
Alternatively, the method also includes applying the 3rd magnetic field, described third party with third direction to described magnetic head
To being parallel to described screen layer and becoming 0 ° of angle with described air bearing face.
It is preferred that the scope of the intensity in described second magnetic field is-800Oe～800Oe.
It is preferred that described output parameter is represented by output voltage.
Alternatively, described output parameter is represented by signal to noise ratio.
It is preferred that described change has a maximum transition, described maximum transition has transition rate, described appearance
The transition rate being permitted value is 8%.
Correspondingly, the present invention provides a kind of device testing magnetic head resistance to elevated temperatures, and described magnetic head includes air
Loading end and two screen layers, described device includes the first magnetic field applying unit, is used for first direction to described
Magnetic head applies the first magnetic field of multiple varying strengths；First measuring unit, for surveying according to described first magnetic field
Flow control one output parameter curve；Second magnetic field applying unit, for applying not to described magnetic head with second direction
The second magnetic field with intensity；Second measuring unit, for according to described second magnetic-field measurement the second output parameter
Curve；And judging unit, it is used for judging that described first output parameter curve and described second output parameter are bent
Whether line exists the change beyond feasible value, thus filters out bad magnetic head.Wherein, described first direction
Being perpendicular to the air bearing face of described magnetic head, described second direction is worn at an anglely with described air bearing face
Crossing described air bearing face, the absolute value of described angle is acute angle.
The present invention provides a kind of device testing magnetic property, and described magnetic head includes air bearing face and two screen layers,
Described device includes the second magnetic field applying unit, for applying varying strength with second direction to described magnetic head
Second magnetic field, described second direction and described air bearing face at an anglely through described air bearing face,
The absolute value of described angle is acute angle；And measuring unit, for according to magnetic described in described second magnetic-field measurement
The output parameter of head, thus test the performance of described magnetic head.
Compared with prior art, the present invention applies with the direction passing ABS with ABS angularly to magnetic head
Second magnetic field, the absolute value of this angle is acute angle, thus measures the output of magnetic head, and this kind magnetization is repeated several times
Operation and measurement operation, finally filter out bad magnetic head in multiple curves of output.The present invention can be the most right
In the case of magnetic head heating, the most then can detect that the most potential generation much noise not
Good magnetic head.Therefore comparing prior art, the method for testing of the present invention is improved.Again and, the present invention can
Detecting the bad magnetic head using general magnetized traditional method to detect completely, accuracy of detection is reliable.
By description below and combine accompanying drawing, the present invention will become more fully apparent, and these accompanying drawings are used for explaining
Embodiments of the invention.
Accompanying drawing explanation
Fig. 1 is the partial perspective view of the simplification of MR read head, which show the general direction of magnetization.
Fig. 2 is the axonometric chart of magnetic head, which show a kind of traditional method of testing.
Fig. 3 a is the axonometric chart of the magnetic head of the present invention.
Fig. 3 b is the partial perspective view of the simplification of MR read head, which show according to one embodiment of the present of invention
The magnetic field of different directions is applied to MR read head.
Fig. 4 a is parallel to horizontal plane according to the first embodiment of the present invention, the ABS illustrating magnetic head, and it applies
The second magnetic field in an acute angle with ABS.
Fig. 4 b is parallel to horizontal plane according to the second embodiment of the present invention, the ABS illustrating magnetic head, and it is executed
The second magnetic field added is in an acute angle with ABS.
Fig. 5 a is the sectional view of the MR read head of the magnetic head shown in Fig. 4 a.
Fig. 5 b is the sectional view of the MR read head of the magnetic head shown in Fig. 4 b.
Fig. 6 is the flow chart that the present invention tests an embodiment of the method for magnetic head resistance to elevated temperatures.
Fig. 7 a～7c is the test curve figure of first concrete instance, and it respectively show MR read head first
Direction and-9 ° ,+9 ° second direction magnetic field under different output voltage curves.
Fig. 8 a～8c is the test curve figure of second concrete instance, and it respectively show MR read head first
Direction and-9 ° ,+9 ° second direction magnetic field under different output voltage curves.
Fig. 9 illustrates an embodiment of the device of the test magnetic head resistance to elevated temperatures of the present invention.
Figure 10 illustrates the flow chart of an embodiment of the method for the test magnetic head performance of the present invention.
Figure 11 illustrates an embodiment of the device of the test magnetic head performance of the present invention.
Detailed description of the invention
Illustrate the several different most preferred embodiment of the present invention below with reference to the accompanying drawings, wherein identical in different figures
Label represents identical parts.As it has been described above, essence of the invention is that offer one test magnetic head is high temperature resistant
The method of performance, it is angularly to apply magnetic field through the direction of ABS to magnetic head with ABS, this angle
Absolute value is acute angle, thus filters out the defect magnetic head occurring bad performance when using in high temperature environments.
The magnetic head being traditionally used for head-slider generally comprises for reading the read head of data from disk and to magnetic
The writing head of dish write data.Read head is generally made up of a MR read head, such as, have current-perpendicular-to-the-plane type
(CPP), the read head such as electric current planar type (CIP), TMR, GMR or AMR.For ease of understanding,
The present invention only describes emphatically CPP-TMR read head.Obviously, those skilled in the art after reading this specification,
It will be appreciated that the present invention is being applied to the situation of other read heads.
Fig. 3 a illustrates a magnetic head 200, and it includes substrate body 201, relative ABS 202 and bottom surface 204
And relative front 203 and trailing edge (not shown) (as shown in fig. 4 a).This ABS 202 is machined to
Suitably flying height.Front 203 is provided with MR read head 210 and writing head 220, specifically, such as figure
Shown in 3b, this MR read head 210 include being formed at the first screen layer 211 on a substrate (not shown),
Secondary shielding layer 212, and layer presss from both sides the MR element 230 between this first, second screen layer 211,212.
Wherein, being provided with a pair hard magnetic layer 240 in the both sides of MR element 230, this same layer of hard magnetic layer 240 is sandwiched in
Between this first, second screen layer 211,212.
Apply first magnetic field with first direction 291 to MR read head 210, this first direction 291 is vertical
In ABS 202, the i.e. first magnetic field with in 90 ° with ABS 202 through ABS 202, this first direction 291
It is referred to as " laterally ".Under the design of the present invention, can apply that there is second direction 292 to MR read head 201
The second magnetic field, to test performance and the characteristic of MR read head 210, this second direction 292 through ABS 202,
And at an angle with this ABS 202, the absolute value of this angle is acute angle.
Specifically, this second direction 292 includes two kinds of situations: one, second direction 292 and ABS 202
Tilt with becoming a positive angle；Its two, second direction 292 tilts with ABS 202 with becoming a negative angle, and wherein this is being just
Angle and negative angle define with quadrant.Specifically, the absolute value of this positive angle and negative angle is acute angle.
For being more fully understood that second direction 292, Fig. 4 a and Fig. 4 b respectively show two embodiments of the present invention,
Magnetic head 200 is arranged to ABS 202 and is parallel to horizontal plane, and the second magnetic field applied becomes sharp with ABS 202
Ground, angle passes ABS 202.Wherein, Fig. 4 a illustrates a positive angle, and Fig. 4 b illustrates a negative angle.Figure
5a and Fig. 5 b is respectively the cross section of the MR read head of the magnetic head of Fig. 4 a and Fig. 4 b.As shown in Fig. 5 a～5b,
It respectively show a positive angle α, negative angle β.
Fig. 6 is the flow chart that the present invention tests an embodiment of the method for magnetic head resistance to elevated temperatures.The method
Comprise the following steps:
Step (601), to be perpendicular to the first direction first magnetic to the magnetic head multiple varying strengths of applying of ABS
, and measure the first output parameter curve；
Step (602), applies the second magnetic field of multiple varying strengths, and measures the with second direction to magnetic head
Two output parameter curves, this second direction and ABS are at an anglely through ABS, and the absolute value of this angle is
Acute angle；And
Step (603), it is judged that whether exist in the first output parameter curve and the second output parameter curve and exceed
The change of feasible value, thus filter out bad magnetic head.
As it has been described above, the one way in which performing step (602) is to control this magnetic head to make ABS and water
Plane is parallel, then applies the second magnetic field with at an angle with ABS through ABS.That is, this magnetic head with
Plane-parallel, the second magnetic field then tilts relative to a vertical line.
Perform step (602) another way be control magnetic head make ABS with the horizontal an angle,
The absolute value of this angle is acute angle, then applies the second magnetic field to magnetic head, and now the second magnetic field is to be perpendicular to water
The direction of plane applies.That is, this head relative horizontal plane.
It is preferred that this angle is in the range of-20 °～20 °, wherein except 0 °.In the present invention, choose relatively
Good angle is-10 ,-9 ,-8 ...-1,1,2,3 ... 10 degree.Quantity for the inclination angle of test needs according to reality
It can be one or more for asking, and for ensureing testing precision, at least chooses two angles and tests.
Specifically, in the present invention, use output voltage is as output parameter, certainly under the design of the present invention,
Other output parameters, as resistance, signal to noise ratio etc. are used as.
Specifically, in step (603), if the change being presented on curve is outside the scope of feasible value,
Then this tested magnetic head is judged as manifesting in high temperature environments not best performance (as produced substantial amounts of noise)
Bad magnetic head, thus be rejected；It is otherwise certified products.As a kind of form of expression, huge change presents
Go out the maximum transition more than 8% of the transition rate.In other words, if the transition rate of the maximum transition of curve of output
More than 8%, then this tested magnetic head is defective products.Intuitively, this defective products can present acutely on curve of output
Shake.
It is preferred that first direction and second direction all can penetrate ABS and/or pass from ABS, and first
The intensity in magnetic field and the second magnetic field is in the range of-800Oe～800Oe.
Alternatively, if desired, can be to magnetic head to be parallel to screen layer and to become with ABS the direction at 0 ° of angle to apply the
Three magnetic fields, to measure the output characteristics of magnetic head.
Fig. 7 a～7c is the curve chart using the method for the present invention to test first concrete instance, and it is respectively
Illustrate MR read head output voltage curve under the action of a magnetic field of different directions.In this embodiment, exist
In the case of each applies magnetic field, the operation of magnetization operation and measurement output voltage is all carried out twice.Figure
7a～7c in turn, show the test curve of three kinds of different magnetic fields: applies the being perpendicular to the first direction of ABS
One magnetic field；To become-9 ° of ground to apply the second magnetic field through the second direction of ABS with ABS；And with ABS
+ 9 ° of ground are become to apply the second magnetic field through the second direction of ABS.
The intensity in the first magnetic field and the second magnetic field is in the range of-800Oe～800Oe.Specifically, to be perpendicular to ABS
The first direction 291 of 202 first magnetic field in the range of magnetic head 210 applies-800Oe～800Oe, measures
First output voltage curve C1.Specifically, this operation is circulated twice, each song tested the most each time
Line chart has two curves.
Specifically, for the second output voltage curve, the inclination angle controlled between the second magnetic field and ABS is-9 °,
Then under this angle, apply multiple the second magnetic field between-800Oe～800Oe, thus measure the second output
Voltage curve C2.Similarly, under the angle of+9 °, measure the second output voltage curve C3.
In above-mentioned curve chart, transverse axis represents magnetic field intensity (unit is Oe), and the longitudinal axis represents that tested magnetic head exists
Output voltage (unit is μ V) after magnetization.
In output voltage curve C1～C3 visible, C3 occurs bigger transition, its inclination angle is+9 °.
Wherein, the maximum transition occurred in C3, it is computed learning that its transition rate is 16.250%, is far longer than and allows
Value 8%.Therefore, can determine that this tested magnetic head is bad magnetic head according to this, this bad magnetic head makes in high temperature environments
Used time can produce substantial amounts of noise.
Fig. 8 a～8c is the curve chart using the method for the present invention to test second concrete instance, and it is respectively
Illustrate MR read head output voltage curve under the action of a magnetic field of different directions.Similarly, Fig. 8 a～8c
In turn, show the test curve of three kinds of different magnetic fields: apply the first magnetic field being perpendicular to the first direction of ABS；
To become-9 ° of ground to apply the second magnetic field through the second direction of ABS with ABS；And to become+9 ° of ground with ABS
Second direction through ABS applies the second magnetic field.
In the present embodiment, bigger shake occur in output voltage curve C5 and C6, its inclination angle is divided
It it not-9 ° and+9 °.Specifically, C6 occurs maximum transition, is computed learning that its transition rate is 18.281%,
It is far longer than feasible value 8%.Therefore, can determine that this tested magnetic head is similarly bad magnetic head according to this, it is at high temperature
Substantial amounts of noise can be produced when using under environment.
Inventor uses the method for testing of the present invention that the sampling of a large amount of magnetic heads was carried out test, finds the present invention's
The measuring accuracy of method of testing is good.In the present invention, two typical embodiments are only enumerated.
Compared with prior art, the present invention applies with the direction passing ABS with ABS angularly to magnetic head
Second magnetic field, the absolute value of this angle is acute angle, thus measures the output of magnetic head, and this kind magnetization is repeated several times
Operation and measurement operation, finally filter out bad magnetic head in multiple curves of output.The present invention can be the most right
In the case of magnetic head heating, the most then can detect that the most potential generation much noise not
Good magnetic head.Therefore comparing prior art, the method for testing of the present invention is improved.Again and, the present invention can
Detecting the bad magnetic head using general magnetized traditional method to detect completely, accuracy of detection is reliable.
It should be noted that first direction and the second direction of above-described embodiment all penetrate ABS, but do not limit
In this.Under the design of the present invention, first direction and second direction also can pass from ABS.
Correspondingly, Fig. 9 illustrates the embodiment that the present invention tests the device of magnetic head resistance to elevated temperatures.As
Shown in figure, this device 900 includes the first magnetic field applying unit 901, and it is for be perpendicular to the first of ABS
Direction applies the first magnetic field of multiple varying strengths to magnetic head；First measuring unit 902, it is for according to first
Magnetic-field measurement the first output parameter curve；Second magnetic field applying unit 903, it is used for second direction to magnetic head
Apply the second magnetic field of varying strength, this second direction with at an angle with ABS through ABS, this angle
Absolute value be acute angle；Second measuring unit 904, it is for bent according to second magnetic-field measurement the second output parameter
Line；And judging unit 905, it for judging in the first output parameter curve and the second output parameter curve is
No existence is beyond the change of feasible value, thus filters out bad magnetic head.
Specifically, this device 900 farther includes the first control unit (not shown), is used for controlling magnetic head,
ABS is made to be parallel to horizontal plane.
Alternatively, this device 900 also includes the second control unit (not shown), is used for controlling magnetic head so that
ABS is with the horizontal an angle, and the absolute value of this angle is acute angle.
Alternatively, in the multiple quasi static test (Quasi-Static Test, QST) of magnetic head, this device
900 can include the 3rd magnetic field applying unit, and it is used for third direction to magnetic head applying the 3rd magnetic field, the 3rd
It is oriented parallel to screen layer and becomes 0 ° of angle with ABS.
The device 900 of the method for testing that this execution is above-mentioned, it is possible to high accuracy filters out and uses out in high temperature environments
The bad magnetic head of existing poorer performance.This device 900 includes the technical characteristic corresponding with above-mentioned method of testing, and
The all advantages described in above-mentioned method of testing can be obtained.
Figure 10 illustrates the flow chart that the present invention tests an embodiment of magnetic head performance, and it at least includes following
Step:
Step (1001), applies the second magnetic field with second direction to magnetic head, and measures the output parameter of magnetic head,
This second direction and ABS are at an anglely through ABS, and the absolute value of this angle is acute angle；
Step (1002), according to the output parameter of the second magnetic-field measurement magnetic head；And
Step (1003), repeats to apply the second magnetic field of varying strength, and measures repeatedly output parameter.
Under the design of the present invention, the one way in which performing step (1001) is to control this magnetic head to make
ABS and plane-parallel, apply the second magnetic field with at an angle with ABS through ABS then.That is,
This magnetic head and plane-parallel, the second magnetic field then tilts relative to a vertical line.
Perform step (1001) another way be control magnetic head make ABS with the horizontal an angle,
The absolute value of this angle is acute angle, then applies the second magnetic field to magnetic head, and now, the second magnetic field is to be perpendicular to
The direction of horizontal plane applies.That is, this head relative horizontal plane.
If desired, in QST, the first direction that can be perpendicular to ABS applies the first magnetic field to magnetic head, or
To be parallel to screen layer and to become with ABS the third direction at 0 ° of angle to apply the 3rd magnetic field, thus test the defeated of magnetic head
Go out characteristic.
Specifically, in the present invention, use output voltage is as output parameter, certainly under the design of the present invention,
Other output parameters, as resistance, signal to noise ratio etc. are used as.
Specifically, in step (603), if the change being presented on curve is outside the scope of feasible value,
Then this tested magnetic head is judged as manifesting in high temperature environments not best performance (as produced substantial amounts of noise)
Bad magnetic head, thus be rejected；It is otherwise certified products.As a kind of form of expression, huge change presents
Go out the maximum transition more than 8% of the transition rate.In other words, if the transition rate of the maximum transition of curve of output
More than 8%, then this tested magnetic head is defective products.Intuitively, this defective products can present acutely on curve of output
Shake.
It is preferred that first direction and second direction all can penetrate ABS and/or pass from ABS, and first
The intensity in magnetic field and the second magnetic field is in the range of-800Oe～800Oe.
Alternatively, if desired, can be to magnetic head to be parallel to screen layer and to become with ABS the direction at 0 ° of angle to apply the
Three magnetic fields, to measure the output characteristics of magnetic head.
Similarly, as it appears from the above, test according to reality, this second direction can penetrate ABS or pass from ABS.
It will be apparent to those skilled in the art that describe according to above-mentioned embodiment of the method, the method for the present embodiment can be wrapped
Include all technical characteristics of said method embodiment and same advantage can be obtained, therefore omitting at this and describe.
Correspondingly, Figure 11 illustrates the embodiment that the present invention tests the device of magnetic head performance.As it can be seen,
This device 1100 includes the second magnetic field applying unit 1102, and it for applying different strong with second direction to magnetic head
Second magnetic field of degree, this second direction and ABS are at an anglely through ABS, and the absolute value of this angle is sharp
Angle；And measuring unit 1103, it is for the output parameter according to the second magnetic-field measurement magnetic head, thus tests
The performance of magnetic head.
Specifically, this device 1100 farther includes the first control unit (not shown), and it is used for controlling magnetic
Head so that ABS is parallel to horizontal plane.
Alternatively, this device 1100 farther includes the second control unit (not shown), and it is used for controlling magnetic
Head so that ABS is with the horizontal an angle, and the absolute value of this angle is acute angle.
Alternatively, in the multiple QST of magnetic head, this device 1100 can include the first magnetic field applying unit (figure
Do not show), it is for applying the first magnetic field with first direction to magnetic head, and this first direction is perpendicular to ABS.
If desired, can arrange the 3rd magnetic field applying unit (not shown), it is for executing to magnetic head with third direction
Adding the 3rd magnetic field, this third direction is parallel to screen layer and becomes 0 ° of angle with ABS.
The device 1100 of the method for testing that this execution is above-mentioned, it is possible to high accuracy filters out and uses in high temperature environments
The bad magnetic head of poorer performance occurs.It will be apparent to those skilled in the art that embodiment according to the method described above
Describing, this device 1100 can include the functional unit corresponding with said method, and obtain identical advantage,
Omit at this and describe.
Above disclosed only presently preferred embodiments of the present invention, can not limit the present invention with this certainly
Interest field, the equivalent variations therefore made according to scope of the present invention patent, still belong to the present invention and contained
Scope.
Claims (42)
1. the method testing MR read head resistance to elevated temperatures, MR read head includes air bearing face and two
Screen layer, described method includes:
Apply the first magnetic field of multiple varying strengths with first direction to described MR read head, and it is defeated to measure first
Go out parameter curve；
Apply the second magnetic field of multiple varying strengths with second direction to described MR read head, and measure the second output
Parameter curve；And
Judge whether the change of described first output parameter curve and described second output parameter curve presents to be more than
The maximum transition of predetermined transition rate, thus filter out bad MR read head；
It is characterized in that: described first direction is perpendicular to the air bearing face of described MR read head, described second party
To at an angle with described air bearing face through described air bearing face, the absolute value of described angle is sharp
Angle.
2. the method for claim 1, it is characterised in that: also include controlling described MR read head,
Make described air bearing face be parallel to horizontal plane, then apply described second magnetic field to described MR read head.
3. the method for claim 1, it is characterised in that: also include controlling described MR read head,
Make described air bearing face with the horizontal described angle, then apply described second to described MR read head
Magnetic field.
4. the method for claim 1, it is characterised in that: the scope of described angle is-20 °～20 °,
Wherein except 0 °.
5. the method for claim 1, it is characterised in that: described first direction and described second party
To penetrating described air bearing face and/or passing from described air bearing face.
6. the method for claim 1, it is characterised in that: also include with third direction to described MR
Read head applies the 3rd magnetic field, and described third direction is parallel to described screen layer and becomes 0 ° with described air bearing face
Angle.
7. the method for claim 1, it is characterised in that: the intensity in described first magnetic field and described
The scope of the intensity in the second magnetic field is-800Oe～800Oe.
8. the method for claim 1, it is characterised in that: described first output parameter curve and institute
State the second output parameter curve to be represented by output voltage.
9. the method for claim 1, it is characterised in that: described first output parameter curve and institute
State the second output parameter curve to be represented by signal to noise ratio.
10. the method for claim 1, it is characterised in that: described predetermined transition rate is 8%.
11. 1 kinds of methods testing MR read head performance, MR read head includes air bearing face and two screen layers,
It is characterized in that, described method includes:
Apply the second magnetic field with second direction to described MR read head, and measure the output ginseng of described MR read head
Number, described second direction and described air bearing face are at an anglely through described air bearing face, described angle
The absolute value of degree is acute angle；And
Repeat to apply the second magnetic field of varying strength, and measure repeatedly output parameter.
12. methods as claimed in claim 11, it is characterised in that: also include controlling described MR read head,
Make described air bearing face be parallel to horizontal plane, then apply described second magnetic field to described MR read head.
13. methods as claimed in claim 11, it is characterised in that: also include controlling described MR read head,
Make described air bearing face with the horizontal described angle, then apply described second to described MR read head
Magnetic field.
14. methods as claimed in claim 11, it is characterised in that: the scope of described angle is-20 °～20 °,
Wherein except 0 °.
15. methods as claimed in claim 11, it is characterised in that: described second direction penetrates described air
Loading end and/or pass from described air bearing face.
16. methods as claimed in claim 11, it is characterised in that: also include being perpendicular to described air and hold
The first direction of section applies the first magnetic field to described MR read head.
17. methods as claimed in claim 11, it is characterised in that: also include with third direction to described
MR read head applies the 3rd magnetic field, and described third direction is parallel to described screen layer and becomes with described air bearing face
0 ° of angle.
18. methods as claimed in claim 11, it is characterised in that: the scope of the intensity in described second magnetic field
It is-800Oe～800Oe.
19. methods as claimed in claim 11, it is characterised in that: described output parameter is by output voltage meter
Show.
20. methods as claimed in claim 11, it is characterised in that: described output parameter is represented by signal to noise ratio.
21. methods as claimed in claim 11, it is characterised in that: also include: judge described output parameter
Change whether present more than predetermined transition rate described in the maximum transition of predetermined transition rate be 8%.
22. 1 kinds of devices testing MR read head resistance to elevated temperatures, MR read head includes air bearing face and two
Screen layer, described device includes:
First magnetic field applying unit, for applying multiple varying strengths with first direction to described MR read head
First magnetic field；
First measuring unit, for according to described first magnetic-field measurement the first output parameter curve；
Second magnetic field applying unit, for applying the second of varying strength with second direction to described MR read head
Magnetic field；
Second measuring unit, for according to described second magnetic-field measurement the second output parameter curve；And
Judging unit, for judging described first output parameter curve and the change of described second output parameter curve
Change and whether present the maximum transition more than predetermined transition rate, thus filter out bad MR read head；
It is characterized in that: described first direction is perpendicular to the air bearing face of described MR read head, described second
Direction and described air bearing face are at an anglely through described air bearing face, and the absolute value of described angle is
Acute angle.
23. devices as claimed in claim 22, it is characterised in that: also include the first control unit, be used for
Control described MR read head so that described air bearing face is parallel to horizontal plane.
24. devices as claimed in claim 22, it is characterised in that: also include the second control unit, be used for
Control described MR read head so that described air bearing face is with the horizontal described angle.
25. devices as claimed in claim 22, it is characterised in that: the scope of described angle is-20 °～20 °,
Wherein except 0 °.
26. devices as claimed in claim 22, it is characterised in that: described first direction and described second party
To penetrating described air bearing face and/or passing from described air bearing face.
27. devices as claimed in claim 22, it is characterised in that: also include the 3rd magnetic field applying unit,
For applying the 3rd magnetic field with third direction to described MR read head, described third direction is parallel to described shielding
Layer also becomes 0 ° of angle with described air bearing face.
28. devices as claimed in claim 22, it is characterised in that: the intensity in described first magnetic field and described
The scope of the intensity in the second magnetic field is-800Oe～800Oe.
29. devices as claimed in claim 22, it is characterised in that: described first output parameter curve and institute
State the second output parameter curve to be represented by output voltage.
30. devices as claimed in claim 22, it is characterised in that: described first output parameter curve and institute
State the second output parameter curve to be represented by signal to noise ratio.
31. device as claimed in claim 22, it is characterised in that: described predetermined transition rate is 8%.
32. 1 kinds of devices testing MR read head performance, MR read head includes air bearing face and two screen layers,
It is characterized in that, described device includes:
Second magnetic field applying unit, for applying the second of varying strength with second direction to described MR read head
Magnetic field, described second direction and described air bearing face are at an anglely through described air bearing face, described
The absolute value of angle is acute angle；And
Measuring unit, for the output parameter according to MR read head described in described second magnetic-field measurement.
33. devices as claimed in claim 32, it is characterised in that: also include the first control unit, be used for
Control described MR read head so that described air bearing face is parallel to horizontal plane.
34. devices as claimed in claim 32, it is characterised in that: also include the second control unit, be used for
Control described MR read head so that described air bearing face is with the horizontal described angle.
35. devices as claimed in claim 32, it is characterised in that: the scope of described angle is-20 °～20 °,
Wherein except 0 °.
36. devices as claimed in claim 32, it is characterised in that: described second direction penetrates described air
Loading end and/or pass from described air bearing face.
37. devices as claimed in claim 32, it is characterised in that: also include the first magnetic field applying unit,
For applying the first magnetic field with first direction to described MR read head, described first direction is perpendicular to described air
Loading end.
38. devices as claimed in claim 32, it is characterised in that: also include the 3rd magnetic field applying unit,
For applying the 3rd magnetic field with third direction to described MR read head, described third direction is parallel to described shielding
Layer also becomes 0 ° of angle with described air bearing face.
39. devices as claimed in claim 32, it is characterised in that: the scope of the intensity in described second magnetic field
It is-800Oe～800Oe.
40. devices as claimed in claim 32, it is characterised in that: described output parameter is by output voltage meter
Show.
41. devices as claimed in claim 32, it is characterised in that: described output parameter is represented by signal to noise ratio.
42. devices as claimed in claim 32, it is characterised in that: also include judging unit, be used for judging
Whether the change of described output parameter presents more than predetermined transition rate described in the maximum transition of predetermined transition rate is
8%.
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| CN104143343B (en) * | 2013-05-09 | 2018-08-10 | 新科实业有限公司 | Head test method and test device |
| CN105372044B (en) * | 2014-08-06 | 2019-03-26 | 深圳长城开发科技股份有限公司 | The precision analytical method and HGA tooling of static mechanical parameter tester |
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| CN101251998A (en) * | 2007-02-19 | 2008-08-27 | 富士通株式会社 | Method of evaluating characteristic of magnetic head |
| CN101807406A (en) * | 2009-01-21 | 2010-08-18 | Tdk株式会社 | Examination method for cpp-type magnetoresistance effect element having two free layers |
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| US8080992B2 (en) * | 2007-11-15 | 2011-12-20 | Infinitum Solutions, Inc. | Write head tester using inductance |
| US9548083B2 (en) * | 2007-12-10 | 2017-01-17 | Infinitum Solutions, Inc. | Read sensor testing using thermal magnetic fluctuation noise spectra |
| US7683610B2 (en) * | 2008-03-03 | 2010-03-23 | Tdk Corporation | Method for inspecting magnetic characteristics of a plurality of thin magnetic heads by means of local application of magnetic field |
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| CN101251998A (en) * | 2007-02-19 | 2008-08-27 | 富士通株式会社 | Method of evaluating characteristic of magnetic head |
| CN101807406A (en) * | 2009-01-21 | 2010-08-18 | Tdk株式会社 | Examination method for cpp-type magnetoresistance effect element having two free layers |
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