CN102760448B - Method and device for testing high-temperature resistance of magnetic head - Google Patents

Abstract

The present invention discloses a method for testing the high temperature resistance performance of a magnetic head, wherein the magnetic head comprises an air bearing surface and two shielding layers, and the method comprises: applying a plurality of first magnetic fields of different strengths to the magnetic head in a first direction, and measuring a first output parameter curve; applying a plurality of second magnetic fields of different strengths to the magnetic head in a second direction, and measuring a second output parameter curve; and judging whether there is a change exceeding an allowable value in the first output parameter curve and the second output parameter curve, so as to screen out a bad magnetic head, wherein the first direction is perpendicular to the air bearing surface of the magnetic head, and the second direction passes through the air bearing surface at an angle with the air bearing surface, and the absolute value of the angle is an acute angle. The present invention can screen out a bad magnetic head with poor high temperature resistance performance with high precision without heating the magnetic head.

Description

Method and device for testing high temperature resistance performance of magnetic head

technical field

The invention relates to a method for testing the performance of a magnetic head, in particular to a method for testing the high temperature resistance of the magnetic head. Moreover, the present invention relates to a device for testing the performance of the magnetic head, in particular to a device for testing the high temperature resistance performance of the magnetic head.

Background technique

A hard disk drive containing multiple spinning platters is commonly used to store data on magnetic media on its platter surfaces, while a movable head containing a read sensor is used to read data from the magnetic tracks on the platter surfaces.

Currently, a magnetoresistive (MR) read head is widely used in mainstream magnetic heads because it is embedded with a higher-sensitivity MR element. Before the magnetic head is used, a series of performance tests must be carried out, such as high temperature resistance performance, dynamic flying height (dynamic flying height, DFH) performance, signal-to-noise ratio (SNR) performance, reliability, stability Wait. For example, a magnetic head with poor high temperature resistance will generate a lot of noise in a high temperature environment. If the magnetic head has poor SNR performance, it will damage the reading stability of the magnetic head, and finally affect the reading performance of the magnetic head. Therefore, the performance test of the magnetic head is very important and necessary.

The method described below is a traditional method for testing MR read heads. As shown in FIG. 1, the MR read head 10 includes two hard magnets 112, an MR element 114 sandwiched between the two hard magnets 112, and two shielding layers 1116 placed on both sides of the MR element 114 and the hard magnets 112. . It is well known that the resistance of the MR element will change with the change of the external magnetic field, so that the output of the MR read head will change. By applying a magnetic field with a direction 19 (hereinafter referred to as "general magnetization direction") parallel to the shielding layer 116 and at an angle of 0° to the air bearing surface 117 (air bearing surface, ABS) of the MR read head 10, the MR reading can be measured. The output voltage of the head, repeat this operation, and then calculate the difference change between the highest output voltage and the lowest output voltage, and this difference change is used to estimate whether the output change is within a certain allowable value. If the output variation is outside the allowable value, the tested magnetic head is judged as a bad magnetic head and discarded. More generally, in the prior art, a magnetic field perpendicular to the direction 18 of the ABS 117 is often applied to measure the output voltage of the magnetic head to detect whether the performance of the magnetic head is qualified.

The above test method of applying a general magnetization direction and a magnetic field perpendicular to the ABS is widely used in the DFH performance test, SNR performance test and reliability and stability test of the magnetic head. However, since the performance requirements of the magnetic head are getting higher and higher, the above magnetization testing method is limited. As for the high temperature resistance performance test of the magnetic head, the high temperature resistance performance is very insensitive to the magnetization in this general magnetization direction. Therefore, the method of the high temperature resistance performance test of the magnetic head is still under study.

US Patent Publication No. 20080049351A1 discloses a method for testing the high temperature resistance performance of a magnetic head. As shown in FIG. 2 , a heating element 35 is provided on the element forming surface 2101 of the magnetic head 21 so as to apply heat and stress to the MR element 32 of the magnetic head 21 . Specifically, when energized, the heating element 35 generates heat. In this case, the MR element 32 and its surrounding materials thermally expand, thereby causing a large amount of internal stress to be generated in the MR element 32. In addition, the MR element 32 also undergoes internal deformation. . Therefore, in this case, the noise value occurring at the output of the MR element 32 is measured, and then it is identified that the magnetic head under test may be potentially deformed in a high-temperature environment to generate noise.

However, since the magnetic head needs to be repeatedly tested in a high-temperature environment with multiple changes, the selection and control of the temperature needs to be very precise. If the temperature is too high, there will be a possibility of damaging good-quality magnetic heads during the test.

Moreover, the above-mentioned method is only applicable to the magnetic head embedded with the heating element, and this method cannot be used for the high-temperature performance test of the magnetic head without the heating element.

Therefore, there is an urgent need for an improved method for testing the high temperature resistance performance of the magnetic head and a method for testing the performance of the magnetic head to overcome the above-mentioned defects.

Contents of the invention

An object of the present invention is to provide a method for testing the high temperature resistance of a magnetic head, which can screen out defective magnetic heads with poor high temperature resistance without heating the magnetic heads.

Another object of the present invention is to provide a method for testing the performance of a magnetic head, which can detect defective magnetic heads that cannot be completely detected by conventional methods of general magnetization.

Another object of the present invention is to provide a device for testing the high temperature resistance of magnetic heads, which can screen out defective magnetic heads with poor high temperature resistance without heating the magnetic heads.

Another object of the present invention is to provide a device for testing the performance of a magnetic head, which can detect defective magnetic heads that cannot be completely detected by conventional methods of general magnetization.

In order to achieve the above object, the present invention provides a method for testing the high temperature performance of the magnetic head, the magnetic head includes an air bearing surface and two shielding layers, the method includes applying a plurality of first to the magnetic head in a first direction with different intensities. magnetic field, and measure the first output parameter curve; apply a plurality of second magnetic fields with different intensities to the magnetic head in a second direction, and measure the second output parameter curve; and judge the first output parameter curve and the second Whether there is a change beyond the allowable value in the output parameter curve, so as to screen out bad heads. Wherein, the first direction is perpendicular to the air bearing surface of the magnetic head, the second direction passes through the air bearing surface at an angle to the air bearing surface, and the absolute value of the angle is an acute angle.

As a preferred embodiment, the method further includes controlling the magnetic head so that the air bearing surface is parallel to a horizontal plane, and then applying the second magnetic field to the magnetic head.

As another preferred embodiment, the method further includes controlling the magnetic head so that the air bearing surface forms the angle with the horizontal plane, and then applying the second magnetic field to the magnetic head.

Preferably, the angle ranges from -20° to 20°, except 0°.

Preferably, said first direction and said second direction penetrate into and/or exit from said air bearing surface.

Optionally, the method further includes applying a third magnetic field to the magnetic head in a third direction, the third direction is parallel to the shielding layer and forms an angle of 0° with the air bearing surface.

Preferably, the strength of the first magnetic field and the strength of the second magnetic field range from -800Oe to 800Oe.

Preferably, the first output parameter curve and the second output parameter curve are represented by output voltages.

Optionally, the first output parameter curve and the second output parameter curve are represented by a signal-to-noise ratio.

Preferably, the change has a maximum jump, the maximum jump has a jump rate, and the allowable value has a jump rate of 8%.

The present invention provides a method for testing the performance of a magnetic head. The magnetic head includes an air bearing surface and two shielding layers. The method includes applying a second magnetic field to the magnetic head in a second direction, and measuring the output parameters of the magnetic head. The second direction passes through the air-bearing surface at an angle to the air-bearing surface, and the absolute value of the angle is an acute angle; and repeatedly applying a second magnetic field of different strengths, and measuring output parameters multiple times, thereby testing the performance of the magnetic head.

As a preferred embodiment, the method further includes controlling the magnetic head so that the air bearing surface is parallel to a horizontal plane, and then applying the second magnetic field to the magnetic head.

As another preferred embodiment, the method further includes controlling the magnetic head so that the air bearing surface forms the angle with the horizontal plane, and then applying the second magnetic field to the magnetic head.

Preferably, the angle ranges from -20° to 20°, except 0°.

Preferably, said second direction penetrates into said air bearing surface and/or passes out of said air bearing surface.

Optionally, the method further includes applying a first magnetic field to the magnetic head in a first direction perpendicular to the air bearing surface.

Optionally, the method further includes applying a third magnetic field to the magnetic head in a third direction, the third direction is parallel to the shielding layer and forms an angle of 0° with the air bearing surface.

Preferably, the strength of the second magnetic field ranges from -800Oe to 800Oe.

Preferably, the output parameter is represented by an output voltage.

Optionally, the output parameter is represented by a signal-to-noise ratio.

Preferably, the change has a maximum jump, the maximum jump has a jump rate, and the allowable value has a jump rate of 8%.

Correspondingly, the present invention provides a device for testing the high temperature resistance of a magnetic head, the magnetic head includes an air bearing surface and two shielding layers, and the device includes a first magnetic field applying unit for applying multiple magnetic fields to the magnetic head in a first direction. a first magnetic field of different strength; a first measuring unit, used for measuring a first output parameter curve according to the first magnetic field; a second magnetic field applying unit, used for applying a second magnetic field of different strength to the magnetic head in a second direction. A magnetic field; a second measuring unit, configured to measure a second output parameter curve according to the second magnetic field; and a judging unit, configured to judge whether there is an exceeding allowable value in the first output parameter curve and the second output parameter curve Changes, thus filtering out bad heads. Wherein, the first direction is perpendicular to the air bearing surface of the magnetic head, the second direction passes through the air bearing surface at an angle to the air bearing surface, and the absolute value of the angle is an acute angle.

The present invention provides a device for testing magnetic properties, the magnetic head includes an air bearing surface and two shielding layers, the device includes a second magnetic field applying unit for applying a second magnetic field of different strengths to the magnetic head in a second direction , the second direction passes through the air bearing surface at an angle to the air bearing surface, the absolute value of the angle is an acute angle; and a measuring unit is configured to measure the output of the magnetic head according to the second magnetic field parameters to test the performance of the magnetic head.

Compared with the prior art, the present invention applies a second magnetic field to the magnetic head in a direction passing through the ABS at an angle with the ABS, the absolute value of which is an acute angle, thereby measuring the output of the magnetic head, repeating this magnetizing operation and Measurement operation, finally screen out bad heads among multiple output curves. The invention can detect bad magnetic heads that potentially generate a lot of noise in a high-temperature environment without heating the magnetic heads at room temperature. Therefore, compared with the prior art, the testing method of the present invention is improved. Moreover, the present invention can detect defective magnetic heads that cannot be completely detected by the traditional method of general magnetization, and the detection accuracy is reliable.

The present invention will become clearer through the following description in conjunction with the accompanying drawings, which are used to explain the embodiments of the present invention.

Description of drawings

Figure 1 is a simplified partial perspective view of an MR read head showing the general magnetization orientation.

FIG. 2 is a perspective view of a magnetic head, which shows a conventional testing method.

Fig. 3a is a perspective view of the magnetic head of the present invention.

Figure 3b is a simplified partial perspective view of an MR read head illustrating the application of magnetic fields in different directions to the MR read head in accordance with one embodiment of the present invention.

Fig. 4a shows that the ABS of the magnetic head is parallel to the horizontal plane and the applied second magnetic field forms an acute angle with the ABS according to the first embodiment of the present invention.

Fig. 4b shows that the ABS of the magnetic head is parallel to the horizontal plane, and the second magnetic field applied thereto forms an acute angle with the ABS, according to the second embodiment of the present invention.

Fig. 5a is a cross-sectional view of the MR read head of the magnetic head shown in Fig. 4a.

Fig. 5b is a cross-sectional view of the MR read head of the magnetic head shown in Fig. 4b.

FIG. 6 is a flowchart of an embodiment of the method for testing the high temperature resistance performance of the magnetic head according to the present invention.

7a-7c are test curves of the first practical example, which respectively show different output voltage curves of the MR read head in the first direction and the magnetic field in the second direction of -9° and +9°.

8a-8c are test curves of the second practical example, which respectively show the different output voltage curves of the MR read head in the first direction and the magnetic field in the second direction of -9° and +9°.

FIG. 9 shows an embodiment of the device for testing the high temperature resistance performance of the magnetic head of the present invention.

FIG. 10 shows a flowchart of an embodiment of the method for testing the performance of the magnetic head of the present invention.

FIG. 11 shows an embodiment of the device for testing the performance of the magnetic head of the present invention.

detailed description

Several different preferred embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like reference numerals in different drawings represent like parts. As mentioned above, the essence of the present invention is to provide a method for testing the high temperature performance of the magnetic head, which applies a magnetic field to the magnetic head in a direction passing through the ABS at an angle to the ABS, and the absolute value of the angle is an acute angle, thereby screening out the magnetic field at high temperature. A defective magnetic head that exhibits poor performance when used in the environment.

A conventional magnetic head for a magnetic head slider generally includes a read head for reading data from a magnetic disk and a write head for writing data to the magnetic disk. The read head is usually constituted by an MR read head, for example, there are current vertical planar (CPP), current in-plane (CIP), TMR, GMR or AMR read heads. For ease of understanding, the present invention only focuses on describing the CPP-TMR read head. Apparently, those skilled in the art can understand the application of the present invention to other read heads after reading this description.

Figure 3a shows a magnetic head 200 comprising a substrate body 201, opposing ABS 202 and bottom surface 204 (shown in Figure 4a), and opposing leading edge 203 and trailing edge (not shown). The ABS 202 is machined to a suitable flying height. An MR read head 210 and a write head 220 are provided on the front side 203. Specifically, as shown in FIG. 3b, the MR read head 210 includes a first shielding layer 211, a second Two shielding layers 212 , and an MR element 230 sandwiched between the first and second shielding layers 211 and 212 . Wherein, a pair of hard magnetic layers 240 are disposed on both sides of the MR element 230 , and the hard magnetic layers 240 are also sandwiched between the first and second shielding layers 211 and 212 .

Applying a first magnetic field to the MR read head 210 has a first direction 291 perpendicular to the ABS 202, i.e. the first magnetic field passes through the ABS 202 at 90° to the ABS 202, the first direction 291 is called for "horizontal". Under the concept of the present invention, a second magnetic field with a second direction 292 can be applied to the MR read head 201 to test the performance and characteristics of the MR read head 210, the second direction 292 passes through the ABS 202 and is in contact with the ABS 202 form an angle whose absolute value is an acute angle.

Specifically, the second direction 292 includes two cases: one, the second direction 292 is inclined at a positive angle to the ABS 202; second, the second direction 292 is inclined at a negative angle to the ABS 202, wherein the positive angle and the negative angle Defined by quadrants. Specifically, the absolute value of the positive angle and the negative angle is an acute angle.

For a better understanding of the second direction 292, Fig. 4a and Fig. 4b show two embodiments of the present invention respectively, the magnetic head 200 is set so that the ABS 202 is parallel to the horizontal plane, and the applied second magnetic field passes through the ABS 202 at an acute angle. Pass ABS 202. Among them, Figure 4a shows a positive angle, and Figure 4b shows a negative angle. Figures 5a and 5b are cross-sections of the MR read head of the magnetic head of Figures 4a and 4b, respectively. As shown in Figures 5a-5b, they respectively show a positive angle α and a negative angle β.

FIG. 6 is a flowchart of an embodiment of the method for testing the high temperature resistance performance of the magnetic head according to the present invention. The method includes the following steps:

Step (601), applying a plurality of first magnetic fields of different intensities to the magnetic head in a first direction perpendicular to the ABS, and measuring a first output parameter curve;

Step (602), applying a plurality of second magnetic fields of different intensities to the magnetic head in a second direction, and measuring a second output parameter curve, the second direction passes through the ABS at an angle to the ABS, and the absolute value of the angle is an acute angle; as well as

Step (603), judging whether there is a change exceeding the allowable value in the first output parameter curve and the second output parameter curve, so as to screen out bad magnetic heads.

As mentioned above, one way of performing step (602) is to control the head so that the ABS is parallel to the horizontal plane, and then apply a second magnetic field across the ABS at an angle to the ABS. That is, the magnetic head is parallel to the horizontal plane, and the second magnetic field is inclined relative to a vertical line.

Another way to perform step (602) is to control the magnetic head so that the ABS forms an angle with the horizontal plane, the absolute value of the angle is an acute angle, and then apply a second magnetic field to the magnetic head. At this time, the second magnetic field is applied in a direction perpendicular to the horizontal plane. That is, the magnetic head is inclined relative to the horizontal plane.

Preferably, the angle ranges from -20° to 20°, except 0°. In the present invention, the preferred angles selected are -10, -9, -8, ... -1, 1, 2, 3, ... 10 degrees. The number of inclination angles used for testing may be one or more according to actual requirements. To ensure testing accuracy, at least two angles are selected for testing.

Specifically, the present invention uses the output voltage as the output parameter, of course, under the concept of the present invention, other output parameters, such as resistance, signal-to-noise ratio, etc., can also be used.

Specifically, in step (603), if the variation presented on the curve is outside the range of the allowable value, then the tested magnetic head is judged as showing poor performance (such as generating a large amount of noise) under high temperature environment Bad magnetic heads are discarded; otherwise, it is a qualified product. As a manifestation, large changes exhibit a maximum jump with a jump rate greater than 8%. In other words, if the maximum transition rate of the output curve is greater than 8%, the tested magnetic head is a defective product. Intuitively, the defective product will show severe jitter on the output curve.

Preferably, both the first direction and the second direction can penetrate into the ABS and/or pass out from the ABS, and the strengths of the first magnetic field and the second magnetic field range from -800Oe to 800Oe.

Optionally, if necessary, a third magnetic field may be applied to the magnetic head in a direction parallel to the shield layer and at an angle of 0° to the ABS to measure the output characteristics of the magnetic head.

7a-7c are graphs of the first practical example tested by the method of the present invention, which respectively show the output voltage curves of the MR read head under the action of magnetic fields in different directions. In this embodiment, the magnetization operation and the operation of measuring the output voltage are performed twice for each application of the magnetic field. Figures 7a to 7c show the test curves of three different magnetic fields in sequence: the first magnetic field is applied in a first direction perpendicular to the ABS; the second magnetic field is applied in a second direction passing through the ABS at -9° with the ABS; and A second magnetic field is applied in a second direction across the ABS at +9° to the ABS.

The strengths of the first magnetic field and the second magnetic field range from -800Oe to 800Oe. Specifically, a first magnetic field in the range of -800Oe˜800Oe is applied to the magnetic head 210 in the first direction 291 perpendicular to the ABS 202 , and the first output voltage curve C1 is measured. Specifically, the operation is looped twice, so there are two curves in each graph for each test.

Specifically, for the second output voltage curve, the inclination angle between the second magnetic field and the ABS is controlled to be -9°, and then multiple second magnetic fields between -800Oe and 800Oe are applied at this angle, so as to measure the first Two output voltage curve C2. Similarly, the second output voltage curve C3 is measured at an angle of +9°.

In the above graph, the horizontal axis represents the magnetic field intensity (unit: Oe), and the vertical axis represents the output voltage (unit: μV) of the measured magnetic head after magnetization.

It can be seen in the output voltage curves C1-C3 that a large jump occurs in C3, and its inclination angle is +9°. Among them, the maximum jump rate in C3 is calculated to be 16.250%, far greater than the allowable value of 8%. Therefore, based on this, it can be determined that the tested magnetic head is a bad magnetic head, and the bad magnetic head will generate a lot of noise when used in a high temperature environment.

8a-8c are graphs of the second practical example tested by the method of the present invention, which respectively show the output voltage curves of the MR read head under the action of magnetic fields in different directions. Similarly, Figures 8a to 8c show the test curves of three different magnetic fields in sequence: the first magnetic field is applied in the first direction perpendicular to the ABS; the second magnetic field is applied in the second direction passing through the ABS at -9° to the ABS ; and applying a second magnetic field in a second direction across the ABS at +9° to the ABS.

In this embodiment, large jitters appear in the output voltage curves C5 and C6, whose inclination angles are -9° and +9°, respectively. Specifically, the largest jump occurs in C6, and its jump rate is calculated to be 18.281%, which is far greater than the allowable value of 8%. Therefore, based on this, it can be determined that the tested magnetic head is also a bad magnetic head, which will generate a lot of noise when used in a high temperature environment.

The inventor has tested a large number of magnetic head samples by using the testing method of the present invention, and found that the testing accuracy of the testing method of the present invention is good. In the present invention, only two typical embodiments are listed.

Compared with the prior art, the present invention applies a second magnetic field to the magnetic head in a direction passing through the ABS at an angle with the ABS, the absolute value of which is an acute angle, thereby measuring the output of the magnetic head, repeating this magnetizing operation and Measurement operation, finally screen out bad heads among multiple output curves. The invention can detect bad magnetic heads that potentially generate a lot of noise in a high-temperature environment without heating the magnetic heads at room temperature. Therefore, compared with the prior art, the testing method of the present invention is improved. Moreover, the present invention can detect defective magnetic heads that cannot be completely detected by the traditional method of general magnetization, and the detection accuracy is reliable.

It should be noted that both the first direction and the second direction in the above embodiment penetrate into the ABS, but it is not limited thereto. Under the concept of the present invention, the first direction and the second direction can also pass through the ABS.

Correspondingly, FIG. 9 shows an embodiment of the device for testing the high temperature resistance performance of the magnetic head according to the present invention. As shown in the figure, the device 900 includes a first magnetic field applying unit 901, which is used to apply a plurality of first magnetic fields of different strengths to the magnetic head in a first direction perpendicular to the ABS; a first measuring unit 902, which is used for according to the first A magnetic field measures the first output parameter curve; the second magnetic field applying unit 903 is used to apply a second magnetic field of different strengths to the magnetic head in a second direction, and the second direction passes through the ABS at an angle with the ABS, and the angle of the The absolute value is an acute angle; the second measurement unit 904 is used to measure the second output parameter curve according to the second magnetic field; and the judging unit 905 is used to judge whether there is an exceeding tolerance in the first output parameter curve and the second output parameter curve The value changes to filter out bad heads.

Specifically, the device 900 further includes a first control unit (not shown in the figure), configured to control the magnetic head so that the ABS is parallel to the horizontal plane.

Optionally, the device 900 further includes a second control unit (not shown in the figure), configured to control the magnetic head so that the ABS forms an angle with the horizontal plane, and the absolute value of the angle is an acute angle.

Optionally, in various quasi-static tests (Quasi-Static Test, QST) of the magnetic head, the device 900 may include a third magnetic field applying unit for applying a third magnetic field to the magnetic head in a third direction, the third Oriented parallel to the shield and at an angle of 0° to the ABS.

The device 900 for executing the above-mentioned testing method can screen out defective magnetic heads with poor performance when used in a high-temperature environment with high precision. The device 900 includes technical features corresponding to the above test method, and can obtain all the advantages described in the above test method.

Fig. 10 has shown the flow chart of an embodiment of the present invention's test magnetic head performance, and it at least comprises the following steps:

Step (1001), applying a second magnetic field to the magnetic head in a second direction, and measuring the output parameters of the magnetic head, the second direction passes through the ABS at an angle to the ABS, and the absolute value of the angle is an acute angle;

Step (1002), measuring the output parameters of the magnetic head according to the second magnetic field; and

Step (1003), repeatedly applying a second magnetic field with different strengths, and measuring output parameters for multiple times.

Under the conception of the present invention, one way of performing step (1001) is to control the magnetic head so that the ABS is parallel to the horizontal plane, and then apply a second magnetic field across the ABS at an angle to the ABS. That is, the magnetic head is parallel to the horizontal plane, and the second magnetic field is inclined relative to a vertical line.

Another way of performing step (1001) is to control the magnetic head so that the ABS forms an angle with the horizontal plane, the absolute value of the angle is an acute angle, and then apply a second magnetic field to the magnetic head. At this time, the second magnetic field is applied in a direction perpendicular to the horizontal plane. That is, the magnetic head is inclined relative to the horizontal plane.

If necessary, in QST, a first magnetic field can be applied to the head in a first direction perpendicular to the ABS, or a third magnetic field can be applied in a third direction parallel to the shield layer and at an angle of 0° to the ABS, thereby testing the output characteristics of the head .

Specifically, the present invention uses the output voltage as the output parameter, of course, under the concept of the present invention, other output parameters, such as resistance, signal-to-noise ratio, etc., can also be used.

Specifically, in step (603), if the variation presented on the curve is outside the range of the allowable value, then the tested magnetic head is judged as showing poor performance (such as generating a large amount of noise) under high temperature environment Bad magnetic heads are discarded; otherwise, it is a qualified product. As a manifestation, large changes exhibit a maximum jump with a jump rate greater than 8%. In other words, if the maximum transition rate of the output curve is greater than 8%, the tested magnetic head is a defective product. Intuitively, the defective product will show severe jitter on the output curve.

Preferably, both the first direction and the second direction can penetrate into the ABS and/or pass out from the ABS, and the strengths of the first magnetic field and the second magnetic field range from -800Oe to 800Oe.

Optionally, if necessary, a third magnetic field may be applied to the magnetic head in a direction parallel to the shield layer and at an angle of 0° to the ABS to measure the output characteristics of the magnetic head.

Similarly, as indicated above, the second direction can pass into or out of the ABS according to actual testing. For those skilled in the art, according to the description of the above method embodiments, the method of this embodiment may include all the technical features of the above method embodiments and obtain the same advantages, so the description is omitted here.

Correspondingly, FIG. 11 shows an embodiment of the device for testing the performance of the magnetic head of the present invention. As shown in the figure, the device 1100 includes a second magnetic field applying unit 1102, which is used to apply a second magnetic field of different strengths to the magnetic head in a second direction, the second direction passes through the ABS at an angle to the ABS, and the absolute value of the angle The value is an acute angle; and a measurement unit 1103, which is used to measure the output parameters of the magnetic head according to the second magnetic field, so as to test the performance of the magnetic head.

Specifically, the device 1100 further includes a first control unit (not shown in the figure), which is used to control the magnetic head so that the ABS is parallel to the horizontal plane.

Optionally, the device 1100 further includes a second control unit (not shown in the figure), which is used to control the magnetic head so that the ABS forms an angle with the horizontal plane, and the absolute value of the angle is an acute angle.

Optionally, in various QSTs of the magnetic head, the apparatus 1100 may include a first magnetic field applying unit (not shown in the figure), which is used for applying a first magnetic field to the magnetic head in a first direction, and the first direction is perpendicular to the ABS.

If necessary, a third magnetic field applying unit (not shown) may be provided for applying a third magnetic field to the magnetic head in a third direction parallel to the shielding layer and at an angle of 0° to the ABS.

The apparatus 1100 for executing the above-mentioned testing method can screen out defective magnetic heads with poor performance when used in a high-temperature environment with high precision. For those skilled in the art, according to the description of the above method embodiment, the device 1100 may include functional units corresponding to the above method and obtain the same advantages, and the description is omitted here.

The above disclosures are only preferred embodiments of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the patent scope of the present invention still fall within the scope of the present invention.

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%.