JPH046809A - Fe group soft magnetic thin film and magnetic head using it - Google Patents

Abstract

PURPOSE:To obtain a magnetic film with high saturation magnetic flux density, high permeability, low magnetostriction constant, and a heat-resistance temperature exceeding 700 deg.C by achieving an Fe group soft magnetic thin film which is expressed by a composition expression of FexAyNz (A is at least one out of Hf, Zr, Ta, Nb, and Ti) and whose composition range is within a specific one. CONSTITUTION:The title item is expressed by a composition expression of FexAyNz (each composition is expressed by atom.% for x-z, A is at least one element out of Hf, Zr, Ta, Nb, and Ti, and N indicates nitrogen) and the composition range is 5<=y<=15, 3<=z<=20, and x+y+z=10. For example, in the above magnetic film, the structure consists of a crystal grain whose average grain diameter is equal to or less than 500Angstrom , a normal RF magnetron sputter device is used for forming the magnetic film, and a compound target where a pellet of A (Hf, Zr, Ta, Nb, and Ti: purity 99.9%) is placed on a target of Fe (purity 99.99%) is sputtered by using a mixed gas of Ar and H2. The amount of A and N is varied by changing the number of A pellets and the partial pressure of the N2 gas.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to core materials of magnetic heads used in magnetic disk drives, VTRs, etc., and particularly has high saturation magnetic flux density, high magnetic permeability, low magnetostriction constant, heat resistance, The present invention relates to a magnetic film having corrosion resistance and a magnetic head using the same.

[Conventional technology]

In recent years, magnetic recording technology has made remarkable progress, and recording densities are being increased in the field of home VTRs to make them smaller and lighter, and in the field of magnetic disk drives to increase their capacity.

In particular, when considering magnetic disk devices, in order to achieve high recording density, the magnetic head is used in a high frequency range, so it is necessary to reduce the inductance of the core, and it is also necessary to narrow the track. It is. However, in the conventional monolithic magnetic head as shown in FIG. 1.theta., it is difficult to reduce the inductance, and it is also very difficult to narrow the track to around 10 .mu.m from the viewpoint of processability.

To compensate for these shortcomings, composite heads have been developed that are constructed by combining a magnetic core and a ceramic slider. Furthermore, in order to generate a strong recording magnetic field capable of recording on high coercivity media, metal-in-gap composite heads are now in practical use, in which a magnetic film with a high saturation magnetic flux density is attached near the core gap. has been made into FIG. 6 is an external perspective view showing an example of a magnetic core of a metal-in-gamble type composite head, and FIG. 7 is an enlarged plan view showing its surface facing a recording medium. The magnetic core halves 1.2 are bonded with glass A to form a magnetic circuit. This magnetic core is fixed to a CaTi0i slider with glass B as shown in FIG. 8 to form a magnetic head.

Corrosion resistance and water resistance of glass are extremely important in the reliability of a magnetic head, but in order to maintain high reliability, it is necessary to use glass with as high a melting point as possible. The bonding temperature needs to be at least about 550°C.

When manufacturing a composite head, two glass bonding steps are required: glass bonding of the magnetic core (1) and glass bonding (If) of fixing the core to the slider.

In order to prevent the glass (A) of the magnetic core from softening or loosening due to the softening of the glass (A) of the magnetic core in the bonding (n) process, the temperature difference between bonding (I) and bonding (II) must be at least as low as possible. A temperature of about 100°C is required. For example, Japanese Patent Application No. 63-12343. Therefore, in order to ensure the reliability of glass B, the glass bonding step (1) needs to be carried out at about 700°C. From these points of view, magnetic films for composite heads are required to have heat resistance of about 700°C.

Conventionally, the material with such heat resistance is Fe-^
A 1-3i alloy (Sendust) fit film is applied to a magnetic head. (Refer to JP-A No. 60-74110, etc.).

However, with the improvement of the coercive force of recording media, magnetic films for magnets with higher saturation magnetic flux density have become necessary.

In recent years, Fe-Ga-5i film (JP-A-61-234509
．． JP 62-104108, etc.) Fe-C multilayer film (JP 6365604, JP 63-80509) Co
and Fe-based composition-modulated nitride films (Japanese Patent Application Laid-Open No. 62-2106
07. Japanese Patent Publication No. 63-57758. Japanese Patent Publication No. 63-2547
08) Co-M-C film (M=Ta.

Ti + Zr + Hf + NJ Mo) (1 Japan Institute of Metals Spring Conference 1989 General Lecture Summary J (128)
, r Japan Institute of Metals Autumn Meeting 1989 General Lecture Summary J (
252).

(253), Fe-MC film (where M=Ti,
Zr0f, V, Nb, Ta) (rIEICE Technical Report J
MR-89-12゜P 9 (1989), 13th Japanese Society of Applied Magnetics Academic Lecture Abstracts (1989), P484
．． The search for magnetic films with high saturation magnetic flux density and excellent heat resistance, such as 485), is underway.

In particular, the Fe-M-C film has a maximum saturation magnetic flux density of 1.7T.
It has a high heat resistance temperature of about 600°C and is promising. This material has a microcrystalline U weave of α-Fe and M carbides,
Microcrystallization reduces anisotropic dispersion, resulting in soft magnetism. Furthermore, since the carbide of M suppresses the growth of α-Fe crystal grains, the heat resistance temperature is also high. The above is from IEICE Technical Report M.
It is described in R-89-12.

In this material, soft magnetism is obtained by generating microcrystals through heat treatment at 450 to 500°C.

[Problem that the invention seeks to solve]

However, this Fe −M −C (M = Hf,
Zr.

The heat resistance temperature in the composition range in which good soft magnetism can be obtained for the Ta...) film is given in IEICE Technical Report JMR-8912, P.
9 (1989) and 13th Japanese Society of Applied Magnetics Academic Lecture Abstracts (1989) P, 484. According to No. 485, the temperature is 600 to 650° C. at most, and when considering application to a composite head, it is necessary to improve the heat resistance by about 50° C.

The object of the present invention is to eliminate the drawbacks of the prior art described above, to have high saturation magnetic flux density, high magnetic permeability, and low magnetostriction constant, and to
The object of the present invention is to provide a magnetic film having the above-mentioned heat resistance temperature and a magnetic head using the same.

[Means for solving problems]

The present invention is directed to Few Ay N11 (where x, y
, z each represents the composition ratio as atomic %, and A is Hf
At least one element selected from the group consisting of ZrTa, Nb, and Ti, N represents N (nitrogen)), and the composition range is 5≦y≦15 3≦2≦20 x+y+z =io.

There is a Fe-based magnetic 51M characterized by the following.

[For production]

Since the formation energy of nitrides of A (Hf, Zr, Ta, Nb, Ti) is very low, Fe (hereinafter referred to as α-Fe) with a bcc structure and A are already formed in the state after film formation.
A structure consisting of nitride microcrystals is formed. α−
Since the Fe crystal grains are microcrystallized, anisotropic dispersion is reduced, and good soft magnetic properties such as high magnetic permeability and low coercive force are obtained. Also, unlike the Fe-MC film described above, a uniform microcrystalline structure is already generated after the film is formed.
Soft magnetism can be obtained even in the as-deposited state.

Furthermore, the nitride of A has low generation energy and is very stable, so it is already sufficiently generated after the film is formed.
The movement of N due to heat treatment is considerably smaller than that in the case of C. Therefore, the growth of α-Fe crystal grains due to heat treatment is suppressed by the nitride of A, and the soft magnetic properties do not deteriorate even if heat treatment is applied during glass welding of a magnetic head.

The heat resistance temperature is related to the amount of A nitride; if the amount is less than the appropriate amount, the heat resistance temperature will be low, and if there is too much M nitride, the temperature resistance will be low.
It precipitates at grain boundaries of Fe, and magnetostatic coupling between Fe microcrystals disappears, resulting in an increase in anisotropic dispersion and deterioration of soft magnetism.

Therefore, in order to obtain good soft magnetism even after heat treatment at a high temperature of 700°C or higher, it is necessary to
and N amounts are desirable. Among them, when Hf is used as A, the heat resistance is the highest, and good soft magnetism can be obtained with high Bs.

〔Example〕

(Example 1) A normal RF magnetron spacing device was used to form the magnetic film of the present invention. A (Hf, Zr, Ta, Nb,
A composite target with a pellet of Ti (purity 99.9%) was placed between Ar (purity 99.999%) and N2 (purity 9
Sputtering was performed using a mixed gas of 9.99%). A
, the amount of N was varied by changing the number of A pellets and the partial pressure of N2 gas.

The sputtering conditions were as follows.

Exhaust vacuum level I
The composition of the magnetic film produced under the conditions of crystallized glass substrate temperature and film thickness without heating of 0.2 micrometers or more was analyzed by EPMA. The saturation magnetic flux density and coercive force of the film were measured using VSM (applied magnetic field 500 e), magnetic permeability was measured using a vector impedance meter, and magnetostriction constant was measured using an optical beam method.

The heat resistance of this magnetic film was determined by heating it to a predetermined temperature in an N2 atmosphere and then measuring its magnetic permeability at room temperature.
Judgment was made based on the temperature below.

FIG. 1 shows the relationship between magnetic permeability (5MII2) and film composition when a Fe-Hf-N film is subjected to heat treatment at 700°C.

As is clear from Figure 1, Hf5-15% in atomic ratio,
With a composition of N3 to 20% and the balance Fe, μS□z >
1000 characteristics are obtained.

Figure 2 shows Fe, s, oHfx, hNIs, a (at
%), which shows the relationship between the magnetic permeability μ5MM2 and coercive force Hc and the heat treatment temperature, it is clear that in the state after film formation (as-depo), u5xNz=1
600. Shows good soft magnetism with Hc=0.80e.

When further heat-treated, μ5M8! >2000. It exhibits a characteristic of Hc<10e, and has a heat resistance temperature of over 700°C.

Figure 3 shows the saturation magnetic flux density Bs of this Fe-Hf-N film.
At a heat treatment temperature of 500° C. or higher, Bs shows a nearly constant value of 1.4T.

Table 1 shows that in addition to Hf, Z is used as A in the Fe-A-N film.
The magnetic properties of films of various compositions using R, Ta, Nb, and Ti under the optimum heat treatment conditions are shown. Moreover, as for heat resistance, the temperature at which μSM)12 was 1000 or less was shown. In addition, μ, -2 is 1000 in all temperature ranges.
Items that do not meet the above requirements are marked with an X.

When A is Zr, Ta, Nb, Ti, the atomic ratio is A
with a composition of 5 to 15%, N3 to 20%, and the balance Fe,
Bs1, 3-1.7 T, μsxgz>1000.
It exhibited the characteristics of Hc≦10e, λ=-1 to 3X10-', and the heat resistance temperature was also 700°C or higher.

FIG. 4 shows changes in the X-ray diffraction patterns due to heat treatment of Feti, oHf++, iN+s, and 4 films. as-d
From the epo state, Fe (α-F
e) (110).

(111) of HfN with (200) plane, (200)
.

A diffraction peak of the (311) plane was observed. α-Fe(1
10) The crystal grain size was determined from the half-width of the peak using the 5cherrer formula, and it was found to be about 60 people.

On the other hand, even after heat treatment at 700°C, α-Fe and Hf-N
A peak was observed, and the α-Fe crystal grain size was approximately 90 mm. In this way, from the as-depo state to 700℃
Since the α-Fe crystal grains are as small as 60 to 90 grains until after the heat treatment, it is thought that good soft magnetism can be obtained over a wide heat treatment temperature range. However, when the heat treatment temperature is raised further to reach a crystal grain size exceeding 500, the magnetic properties deteriorate significantly.

FIG. 5 shows X-ray diffraction patterns of Fe-If-N films of various compositions after heat treatment at 700°C. If the amount of If and N is excessive with respect to the composition range of the present invention shown in FIG.
It can be seen that sufficient N is generated and Fe grain growth is suppressed. However, the reason why good soft magnetism cannot be obtained is that HfN precipitates at the grain boundaries of Fe.
This is presumed to be because the magnetostatic coupling between the microcrystals weakens and anisotropic dispersion increases.

On the other hand, when Hf and N are small, a sharp peak of α-Fe is observed, indicating grain growth of Fe. Since Fe has a large magnetocrystalline anisotropy, it is thought that the soft magnetism deteriorates rapidly due to this grain growth.

As mentioned above, there is an optimal amount of Hf and N,
In Hf5-15%, N3-20% and balance Fe composition, heat resistance 700℃ or more, μ5M+42 > 100
Good characteristics of 0 can be obtained. The crystal structure at this time is F
It is composed of microcrystals of e and HfN.

(Example 2) Next, an example will be shown in which the Fe-Hf-N film according to the present invention is applied to magnetism/node.

FIG. 6 is an external perspective view showing an example of a magnetic head core to which the magnetic film of the present invention is applied, and FIG. 7 is an enlarged plan view showing the surface facing the recording medium. This magnetic head core is
It was fixed with glass to a CaTiOx slider as shown in the figure, and attached to a gimbal for evaluation as a magnetic head for a hard disk drive.

FIG. 9 shows a magnetic head using a magnetic film according to the present invention, F
e-A7! The relationship between the medium coercive force and the critical recording density, Dso (KFCl), measured using a magnetic head using a -5i film is shown. Fe -11fN with a large Bs of 1.4T
When a film is used, sufficient recording is possible because a strong recording magnetic field can be generated without saturating the tip of the magnetic core even when the medium coercive force increases to 15,000 e or more, and as the medium coercive force increases. will also increase. On the other hand, Fe-Al-3i
If a film is used, the medium coercive force will be 15,000e or more. will decrease.

Therefore, it was confirmed that by using the magnetic head using the Fe-If-N based magnetic film of the present invention, it is possible to write sufficiently even on a medium having a coercive force of 20,000e. In addition, when we compared the reproduction output using a medium with a coercive force of 10,000e, we found that Fe-Hf-N film and Fe-A
No difference was observed when the l-5i film was used.

[Effect of the invention] As explained above, according to the present invention, Fe-A-N (A=Hf, Zr, Ta, Nb
, Ti) film has a high saturation magnetic flux density (1.3~1.T),
High magnetic permeability (1000 or more), low coercive force (10e or less),
It has the characteristics necessary for a magnetic head material, such as a low magnetostriction constant (-1X10-b to 3X10-'') and high heat resistance (700°C or higher).

Therefore, when this magnetic film is used as a magnetic head magnetic pole, a strong magnetic field can be generated at the tip of the magnetic pole without causing magnetic saturation even if the film is about 0.2μ thin, allowing ultra-high-density magnetic recording. can be achieved.

Further, since the magnetic film of the present invention can be formed by a normal RF magnetron sputtering method, the manufacturing method is simple, the manufacturing cost is low, and high reliability can be ensured.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram showing the relationship between the composition and magnetic permeability of the Fe-Hf-N film of the present invention after heat treatment at 700°C, and Figure 2 shows the relationship between the heat treatment temperature and magnetic permeability of Fe-Hf-N#. Figure 3 is a characteristic diagram showing the relationship between coercive force and saturation magnetic flux density. Figure 4 is a characteristic diagram showing the relationship between heat treatment temperature and saturation magnetic flux density for Fe-Hf-N films. Figure 5 shows changes in line diffraction patterns for Fe-H with various compositions.
A diagram showing the X-ray diffraction pattern of the f-N film after heat treatment at 700°C, and FIG. 6 is a perspective view showing an example of the core of a magnetic head (metal-in-gap type composite head) to which the magnetic film of the present invention is applied. 7 is an enlarged plan view showing the surface facing the magnetic recording medium, FIG. 8 is an external perspective view of a magnetic head with an embedded magnetic core, and FIG. 9 is a magnetic head using an Fe-Hf-N film. FIG. 10 is a characteristic diagram showing the relationship between medium coercive force and critical recording density measured using the conventional monolithic head, and is a perspective view of the appearance of a conventional monolithic head. 1: Magnetic core half, 2: M1 core half, 3: M1 film, 4: Magnetic gap, 5 Ni glass A, 6: Magnetic core, 7
:Slider, 8 Nigarasu B19: Magnetic core, 10: Magnetic gap, 11 Nislider: Coil. Ritsumeikan Co., Ltd. Fig. 6 Media coercive force Hc (Oe) Fig.

Claims (3)

[Claims] (1) Fe_xA_yN_z (x, y, z each represent the composition ratio as atomic %, A is Hf, Zr, Ta
, Nb, and Ti, and N represents nitrogen), and the composition range is 5≦y≦15 3≦z≦20 x+y+z=100 An Fe-based soft magnetic thin film characterized by the following. (2) The Fe-based soft magnetic thin film according to claim 1, wherein the structure of the magnetic film is composed of crystal grains having an average grain size of 500 Å or less. (3) A magnetic head characterized by using the Fe-based soft magnetic thin film according to claims 1 and 2.