JP2712631B2 - Soft magnetic thin film and magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used for a magnetic recording device or the like and a soft magnetic thin film used for the magnetic head.

2. Description of the Related Art In recent years, as magnetic recording devices have become smaller and larger in capacity,
There is a high demand for higher density and various developments have been made. The medium needs to have a high coercive force and a high saturation magnetic flux density. In order to satisfy this condition, the medium is shifting from a medium coated with oxide fine particles to a medium in which a ferromagnetic thin film having a high magnetic flux density is manufactured by a vacuum apparatus. A magnetic head capable of sufficiently recording such a medium needs to output a high recording magnetic field without being magnetically saturated. For this purpose, the magnetic head must be made of a material having a saturation magnetic flux density as high as possible. Generally, a magnetic head is made of ferrite, which is a soft magnetic material, has a magnetic gap on a surface facing a medium, and performs recording and reproduction using this magnetic gap. When recording high-density media, to prevent magnetic saturation,
The use of a soft magnetic thin film having a higher saturation magnetic flux density than ferrite for at least a part of a magnetic core has been promoted. The development of a thin-film magnetic head in which the entire magnetic circuit of the magnetic head is formed of a soft magnetic thin film and a magnetic head using a soft magnetic thin film only in the vicinity of a gap where saturation is likely to occur are being vigorously pursued. At this time, the factors that affect the characteristics of the magnetic head are:
This is a characteristic of the soft magnetic thin film. This thin film is required to have a high saturation magnetic flux density and a high initial magnetic permeability. As soft magnetic thin film, amorphous alloy, Ni-Fe, Fe-
The development of Fe-based alloys such as Al-Si has been promoted, and their properties are being improved.

Among these soft magnetic thin films, Fe-Ai-Si-based soft magnetic thin films having a high saturation magnetic flux density of 10 kG and excellent wear resistance and heat resistance have recently been widely used. It has been known that the magnetic properties of this soft magnetic thin film are conventionally strongly influenced by crystal magnetic anisotropy and magnetostriction determined by the film composition. Therefore, in order to obtain excellent magnetic properties, it is necessary to determine a composition that reduces crystal magnetic anisotropy and magnetostriction.

In addition to optimizing the film composition, it is necessary to consider the crystal structure. Since the Fe-Al-Si soft magnetic thin film is a crystalline material, the influence of the underlayer is strong, and the crystal structure is controlled by selecting a substrate to improve its magnetic properties. The present applicant has proposed, for example, Japanese Patent Application No. 60-241320 or 63-63 to improve the characteristics of Fe-Al-Si soft magnetic thin films.
241315 etc. have been disclosed. According to this, a film having excellent magnetic properties is obtained as the film in which the (211) plane is preferentially oriented.

Problems to be Solved by the Invention However, in the conventional soft magnetic thin film, the initial magnetic permeability greatly varies depending on the forming conditions and the like, and the conventional soft magnetic thin film is used for the medium facing surface of the magnetic head, or all the thin films are used. When used for the core of the magnetic head formed in the above, there is a problem that the magnetic characteristics vary.

Means for Solving the Problems Fe-Al-Si is preferentially oriented to the (211) plane or the (110) plane, and its crystal grain size is 250 ° or less and 290 or less, respectively.
It was set to more than Å and less than 310Å.

Operation With this configuration, the crystal structure of the thin film can be improved, and no stress is generated in the thin film. .

Examples Hereinafter, examples of the present invention will be described in detail.

The Fe-Al-Si soft magnetic thin film was formed by a sputtering method. The magnetic properties of the Fe—Al—Si thin film are affected not only by the film composition but also by the crystal structure. Therefore, the magnetic characteristics are affected by the film formation conditions that cause a change in the crystal structure and the type of the apparatus. FIG. 1 shows the relationship between the degree of orientation of the (211) plane and initial magnetic permeability obtained by x-ray diffraction in films formed under various film forming conditions and apparatuses. Here, the horizontal axis indicates the degree of orientation of the (211) plane, and the vertical axis indicates the initial magnetic permeability. The degree of orientation means that the X-ray intensity of the (211) plane obtained by X-ray diffraction is M (211), and the X intensity of the (110) plane is M
When (110) is used, it is expressed by the following equation. Here, when the degree of orientation is Z, Z = M (211) / (M (211) + M (110)) Here, the case where the degree of orientation Z is 0 is a film formed by preferentially orienting the (110) plane. This means that the orientation degree M of 1 means that the (211) plane has shifted priority. As the (211) plane is preferentially oriented, the initial magnetic permeability increases. However, the initial magnetic permeability of the preferentially oriented film varies greatly from 1300 to 5000. The cause largely depends on the film forming conditions or the type of the apparatus.

With respect to the various films described above, the crystal grain size was measured based on the half width of X-ray diffraction, and the relationship with the initial magnetic permeability was examined. The result was as shown in FIG.

In the film in which the (211) plane is preferentially oriented, the initial magnetic permeability increases with the refinement of the crystal grain size. On the other hand, in the film in which the (110) plane is preferentially oriented, the maximum initial magnetic permeability is shown at a crystal grain size of 300 °. This indicates that there is a difference in the crystal grain size showing the best magnetic properties between the film in which the (211) plane is preferentially oriented and the film in which the (110) plane is preferentially oriented. Considering the magnetic head efficiency, the higher the initial magnetic permeability, the higher the efficiency and the higher the output. To obtain an efficiency of 90 or more, an initial magnetic permeability of 2000 or more is required. In order to obtain this initial magnetic permeability, the (211) preferred orientation film should be 250 ° or less,
For the (110) preferential orientation film, producing a film having a thickness of 290 ° or more and 310 ° or less provides a high initial magnetic permeability and can produce an efficient magnetic head.

FIG. 3 shows the relationship between the crystal grain size and the lattice constant. Given the above grain size, the lattice constant of each film is equal to that of the bulk sendust material. This bulk sendust material has been sufficiently heat treated and has very low stress. As described above, when the crystal grain size of the film with the (211) plane preferentially oriented is 150 mm or less, and the crystal grain size of the film with the (110) plane preferentially oriented is 290 mm or more and 310 mm or less, the stress becomes very small. . FIG. 4 is a perspective view showing a magnetic head using the soft magnetic thin film thus formed. 4th
In the figure, reference numerals 1 and 2 denote cores each made of a magnetic material such as ferrite, and the core 2 is provided with a winding groove 2a. Reference numeral 3 denotes a metal magnetic film formed on the core 1, and the metal magnetic film 3 is formed of Fe-Al-Si. The metal magnetic film 3 has the (211) plane preferentially oriented and has a crystal grain size of 150 mm.
し た Created as below. As described above, the (110) plane is preferentially oriented and the crystal grain size of the metal magnetic film 3 is 2 as described above.
The same effect can be obtained even if it is formed to be 90 ° or more and 310 ° or less. Numeral 4 is a non-magnetic material serving as a magnetic gap.
In the magnetic head formed as described above, the initial magnetic permeability of the metal magnetic film 3 is improved, the stress applied to the core is reduced, and the output is increased, and the magnetic characteristics are improved. Also, the pseudo output by the pseudo gap was not so much.

Therefore, three types of magnetic heads having the structure shown in FIG. 4 were prepared and evaluated by using three types of Fe—Al—Si films having different crystal grain sizes in the (211) preferred orientation film. The first magnetic head uses a metal magnetic film having a particle size of 150 °, the second magnetic head uses a metal magnetic film having a particle size of 250 °, and the third magnetic head uses a metal magnetic film having a particle size of 350 °. Comparing these three types of magnetic head outputs, assuming that that of the first magnetic head is 1,
The second magnetic head is 0.92 and the third magnetic head is 0.55
Becomes As described above, if a head is manufactured using a thin film having an optimum crystal grain size, a magnetic head that can obtain high efficiency, that is, a high output, can be manufactured. The first magnetic head and the second magnetic head are made of ferrite and Fe-
Almost no pseudo output easily generated at the interface of the Al-Si thin film is detected. The reason for this is that the thin film used has a small stress and good magnetic properties, and furthermore, damage to the ferrite due to the stress of the metal magnetic film is small. Fe
By optimizing the crystal grain size of the magnetic thin film made of -Al-Si, it is possible to reduce not only the output of the magnetic head as shown in FIG.

Another embodiment is shown in FIG. FIG. 5 shows a magnetic head composed entirely of thin films. In FIG. 5, 5 is a substrate made of a nonmagnetic material, 6 is a lower magnetic layer formed on the substrate 5 and made of Fe-Al-Si, and the lower magnetic layer 6 has a (211) plane preferential orientation. Then, the crystal grain size was made to be 150 ° or less. As described above, the lower magnetic layer 6 has the (110) plane preferentially oriented and has a crystal grain size of 290Å.
The same effect can be obtained even if it is formed to be not less than 310 °. 7 is a gap layer formed on the lower magnetic layer 6, 8 is an insulating film formed on the gap layer 7, 9 is a coil layer formed on the insulating film 8, and 10 is a coil layer 9. An insulating film formed on the insulating film 8 for application, 11 is an insulating film 9
The upper magnetic layer 11 was formed so that the (211) plane was preferentially oriented and the crystal grain size was 150 ° or less. As described above, the upper magnetic layer 11 has the (110) plane preferentially oriented,
Similar effects can be obtained even if the crystal grain size is formed to be 290 ° or more and 310 ° or less. Reference numeral 12 denotes a protective layer formed on the upper magnetic layer 11. In the magnetic head thus formed, the upper magnetic layer 11 and the lower magnetic layer 6 are formed such that the (211) plane is preferentially oriented and the crystal grain size is 150 ° or less, so that the initial magnetic permeability is large and the output can be increased. . Similar effects can be obtained by forming the lower magnetic layer 6 and the upper magnetic layer 11 such that the (110) plane is preferentially oriented and the crystal grain size is 290 ° or more and 310 ° or less.

Effects of the Invention By making the Fe-Al-Si thin film a crystal grain size of 250 ° or less for the (211) plane preferred orientation film and 290 ° or more and 310 ° or less for the (110) plane preferred orientation film, the stress is small and the magnetic properties are reduced. Good film can be provided.

[Brief description of the drawings]

1 is a graph showing the relationship between the degree of orientation and the initial magnetic permeability, FIG. 2 is a graph showing the relationship between the crystal grain size and the initial magnetic permeability, and FIG. 3 is a graph showing the relationship between the lattice constant and the crystal grain size. FIG. 5 is a perspective view of a magnetic head according to one embodiment of the present invention, and FIG. 5 is a sectional view showing another embodiment. 1, core 2a winding groove 3 metal magnetic film 4 non-magnetic material 5 substrate 6 lower magnetic layer 7 gap layer 8 insulating film 9 coil layer 10 ... insulating film 11 ... upper magnetic layer 12 ... protective layer

Claims (4)

(57) [Claims] (1) The material is formed of an Fe-Al-Si-based material,
1) It has a crystal structure with preferentially oriented planes and a crystal grain size of 250 mm
A soft magnetic thin film characterized by the following. 2. The method according to claim 1, which is formed of a Fe--Al--Si based material.
0) It has a crystal structure in which the plane is preferentially oriented, and the crystal grain size is 290 mm
A soft magnetic thin film characterized by being not less than 310 mm. 3. A soft magnetic thin film according to claim 1 formed on said core, said soft magnetic thin film being formed on said core via a non-magnetic material serving as a magnetic gap. A magnetic head characterized by having another core formed. 4. A substrate, a lower magnetic layer formed on the substrate, a gap layer formed on the lower magnetic film and serving as a magnetic gap, and provided on the gap layer;
A coil layer sandwiched between insulating layers, and an upper magnetic layer formed on the coil coil and provided so as to form a magnetic circuit with the lower magnetic layer, wherein the lower magnetic layer and the upper magnetic layer 3. A magnetic head comprising at least one of the soft magnetic thin films according to claim 1 or 2.