JPH03181008A - magnetic head - Google Patents

Abstract

PURPOSE:To obtain the novel high saturation magnetization soft magnetic film which has a soft magnetic characteristic and has no pseudo signals in reproduction signals by inserting an underlying layer which consists of specific elements and in which at least a part of the elements are oxides between a ferromagnetic film and an oxide substrate. CONSTITUTION:The underlying part 3 which consists of at least one kind selected from the group of Cr, Mn, Fe, Co, Ni, Cu, Zn, Si, Mo, and W and in which at least a part thereof are oxides, is inserted between the ferromagnetic metallic film 2 and the oxide substrate 1. Such underlying material is not only free from its own diffusion and is also more impervious to oxygen than 'Permalloy(R)'. Glass packing at a high temp. of >=500 deg.C is possible in this way and a glass layer 4 having sufficient strength is formable when this heat resistant high saturation magnetic flux density film is used for the magnetic head of a magnetic recorder, more particularly the magnetic head of a metal-in-gap type.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head used in magnetic disk drives, VTRs, etc., and particularly relates to a magnetic head with a high saturation magnetic flux density.

The present invention relates to a magnetic head using a ferromagnetic film having high magnetic permeability, high heat resistance, and high corrosion resistance as a magnetic pole material.

[Conventional technology]

In recent years, magnetic recording technology has made remarkable progress, and recording density is being improved. In order to increase the recording density, it is necessary to use a recording medium with high coercive force.

Furthermore, in order to magnetize a recording medium with a high coercive force, a magnetic pole material having a high saturation magnetic flux density is required. For this reason, Ni--Fe alloy (permalloy) and Co-based amorphous alloy thin films are beginning to be used as magnetic pole materials in place of conventional ferrite and the like. Furthermore, in addition to having a high saturation magnetic flux density, the magnetic pole material is required to have a high magnetic permeability in order to improve recording and reproducing efficiency. It is also required to have heat resistance and corrosion resistance that can withstand the heating process in the process of forming a magnetic head and maintain high magnetic permeability.

As such a magnetic pole material, Japanese Patent Application Laid-Open No. 63-236304
.

As shown in Japanese Patent Application Laid-Open No. 64-042108, Fe
an element selected from the group of B, C, N, and P; and Ti.

A material to which elements selected from the group of Zr, I(f, V, Nb, Ta, Mo, W, etc.) are simultaneously added has been reported. Also, according to JP-A-63-39106, a material made of a ferromagnetic oxide Magnetic Hen 1 by depositing a ferromagnetic metal film inside the magnetic core
It has been reported that when configuring .

[Problem to be solved by the invention]

The present inventors fabricated a magnetic head by forming a Fe-Ta-C-based ferromagnetic material in a Mn-Zn ferrite core via a high permeability permalloy layer, and examined the recording and reproducing characteristics.
A supplementary experiment to the above report was conducted. However, as a result of this experiment, the present inventors confirmed that when the magnetic core is bonded by glass bonding at a temperature of 400° C. or higher, the effect of a pseudo gap appears and the reproduced waveform is distorted. This is because Ta in the ferromagnetic material passes through the permalloy layer and reacts with oxygen in the Mn-Zn ferrite at temperatures above 400°C, resulting in T at the interface.
This is thought to be due to precipitation of a oxide. In addition, when the sample prepared as a dummy was analyzed in the depth direction by Auger electron spectroscopy, it was found that Ni, which is a component of permalloy, is mixed with Mn-Zn ferrite and Fe-Ta.
It was confirmed that it existed at the interface of the -C-based ferromagnetic film with almost no diffusion. In this experiment, if permalloy was not inserted at the boundary between the magnetic core and the ferromagnetic metal film, the Fe-Ta-C ferromagnetic film and the Mn-Zn ferrite core would react and form the Fe-Ta-C system. The ferromagnetic film oxidizes,
It has been found that the material no longer exhibits soft magnetic properties.

In other words, it was confirmed that the insertion of the permalloy layer has the role of preventing the reaction between the Fe-Ta-C ferromagnetic film and the Mn-Zn ferrite core, but this permalloy layer cannot suppress oxygen diffusion. It is considered that the influence of the pseudo gap could not be suppressed, and a pseudo signal appeared in the reproduced signal.

Therefore, an object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a novel high-saturation magnetization method that maintains soft magnetic properties even after heat treatment such as glass filling at high temperatures, and that produces no pseudo signals in the reproduced signal. An object of the present invention is to provide a magnetic head using a soft magnetic film.

[Means to solve the problem]

The present inventors have continued intensive research to solve the above-mentioned problems.
a, Va, group VIa elements and mb.

Ferromagnetic film containing rvb, vb group elements 1 As a typical example, in a magnetic head formed by forming a ternary alloy containing 70% or more of Fe or Co on an oxide substrate, a ferromagnetic film and an oxide Cr + M n between the physical substrates,
F e g Co e N x * Cu y Z n
It has been found that it is sufficient to insert an underlayer made of at least one element selected from the group of tSi, Mo, and W, and at least a portion of which is an oxide. Here, it was also confirmed that the desirable thickness of the underlayer is 50 nm.

[Effect]

As mentioned above, between the ferromagnetic metal film and the oxide substrate, Cr,
Mn, Fe, Co, Ni, Cu, Zn.

It has been confirmed that a magnetic head free from the effects of pseudo gaps can be obtained by inserting an underlayer made of at least one element selected from the group of Si, Mo, and W, at least a portion of which is an oxide. . As a result of studies conducted by the present inventors, we found that when these underlying materials are inserted, the ferromagnetic metal film and the oxide substrate do not diffuse into the ferromagnetic film even when heated to 600°C. It was confirmed that there exists between

Although almost no diffusion was observed when permalloy was used, it was noticed that the oxygen concentration distribution was different. 6
After heat treatment at 00°C, the magnetic film was coated with EPMA (Electro
As a result of analysis using the ferromagnetic film (n Probe Micro Analysis) method, attention was paid to the oxygen concentration in the ferromagnetic film, and it was found that Cr, Mn, Fe, Go, Ni, and Cu.

When a base material such as Zn, Si, Mo, or W is inserted, the oxygen concentration in the ferromagnetic film is 0.5 to 1.5 at%, but when Permalloy is used as the base layer, it is 2 to 2%. It turned out to be 5 at%. In other words, it has become clear that when Permalloy is used as an underlayer, Permalloy itself does not diffuse, but M elements generated from the oxide substrate easily pass through, partially oxidizing the ferromagnetic film.

Conventionally, when a head is manufactured by forming a sendust alloy or the like on a ferrite substrate, if permalloy is used as an underlayer, such oxidation of the ferromagnetic film does not occur and the influence of the pseudo gap does not appear.

The cause of oxidation when using the ferromagnetic film of the present invention is that the IVa and VA group elements present in the ferromagnetic film combine with the MB and RVB groups in the ferromagnetic film to form carbides and borides. Even if the ferromagnetic film has a high affinity for oxygen, it is presumed that the oxide substrate is reduced and oxygen is drawn into the ferromagnetic film. That is, it seems that the ferromagnetic film of the present invention is more easily oxidized than the conventional ferromagnetic film.

On the other hand, it was found that the base material of the present invention not only does not diffuse itself, but also is less permeable to oxygen than permalloy.

The present inventors have also conducted similar studies on Fe-AM alloys, Co-Nb alloys, etc. as underlayers, but found that pseudo-gap effects may appear in compositions containing a large amount of AQ and Nb. confirmed. Similarly, we also investigated a Ni-Fe alloy with a composition different from permalloy, but N
It has become clear that excellent regeneration characteristics without the influence of pseudo gaps can be obtained when the amount of different elements added is small, even with single metals such as i and Fe, or alloys.

〔Example〕

Examples of the present invention will be given below and will be explained in more detail with reference to figures and tables.

[Example 1] A ferromagnetic film containing Fe and Co as main components and an underlayer were formed on a Mn-Zn ferrite substrate using an RF sputtering device. Sputtering was performed under the following conditions.

Sputtering gas...Ar Ar gas pressure in the device...1.5Pa Input power
・・・・・・・・・・・・・・・・・・・・・ 350W target board distance・・・55mm Substrate temperature・・・・・・・・・・・・・・・・・・・・・・・・・・・
Degreased and cleaned in advance at a temperature of 50 to 100°C or higher.
After forming the underlayer shown in Table 1 on a Mn-Zn ferrite substrate whose surface was processed into a sawtooth shape, a ferromagnetic film was formed thereon. The thickness of the underlayer was 20 nm, and the thickness of the ferromagnetic film was 3 μm.

The samples obtained in Table 1 were once heat-treated in a magnetic field at 500°C for 1 hour to control the magnetic anisotropy, and then a gap layer of 5iOz with a thickness of 0.1 μm was formed.

Next, glass filling was performed at 480°C to form the ferromagnetic film and M
A magnetic herad core made of n-Zn ferrite was fabricated. FIGS. 1 and 2 show the structure of the magnetic herad core produced in this manner.

The recording and reproducing characteristics of the obtained magnetic head core were evaluated using a magnetic tape with a coercive force of 1600 0e. The output of the pseudo signal due to the influence of the pseudo gap measured at this time is
Shown in the table. For reference, the table also shows the output of pseudo signals when Permalloy is used as the base layer and when a Ni--Fe alloy having a composition similar to Permalloy is used as the base layer. As is clear from the table, when a Ni-Fe alloy with a composition close to permalloy is used for the underlayer, the pseudo signal shows a value of 3 dB or more, but a trace amount of only a few percent of single metals such as Ni or Fe or different elements is used as the underlayer. Only Ni added.

When Fe was used for the underlayer, the pseudo signal was reduced to 2 dB or less. In addition to Ni and Fe, Cr.

It was confirmed that even when metals such as Mn, Co, Cu, Zn, Si, Mo, and W were used as the underlayer, a pseudo signal of 2 dB or less was exhibited, and the passage of oxygen from the ferrite to the ferromagnetic film was suppressed. .

In the table, the ferromagnetic metal film and underlayer indicate the composition of the target during film formation. Therefore, it is expected that one composition will change after the head core is formed because it undergoes a glass filling process. For example, when the underlying layer was analyzed in the depth direction using Auger electron spectroscopy, oxygen was also detected where the underlying layer existed, and it became clear that the underlying layer was partially oxidized.

The ferromagnetic film of the present invention has Fe and Co as main components, and I
Va, Va group elements Ti, Zr, and Hf.

Elements such as V, Nb, Ta, etc. and B of group IIIb and IVb elements
.

It contains elements such as C and N. This ferromagnetic film is made of Fe,
It becomes a microcrystalline film mainly composed of Co and exhibits soft magnetic properties. In fact, as a result of examination using the xi diffraction method, 400℃
The crystal structure of the film heat-treated with Fe is the main component.
It had a body-centered cubic structure, and when Co was the main component, it had a hexagonal close-packed structure. However, the X-ray diffraction peak of the main component was extremely broad, making it clear that it was composed of microcrystalline grains. At this time, in order to form a microcrystalline film containing Fe and Go as main components, the preferred addition amount of IVa and Va group elements is 0.5 to 10 at%, and the addition amount of IIIb and IVb group elements is 1 to 20 at%. %Met.

Incidentally, when this ferromagnetic film is filled with glass, it absorbs oxygen from ferrite and is easily oxidized at IVa.

Ti, Zr, Hf, V, and Nb, which are Va group elements.

This is thought to be because elements such as Ta have a high affinity with oxygen. By the way, the ferromagnetic film of the present invention containing these IVa and Va group elements not only reacts with oxygen from an oxide substrate such as ferrite, but also reacts with the filled glass. In this case, the reaction could be prevented by inserting the underlayer of the present invention between the ferromagnetic film and the filled glass. The thickness of the base layer at this time was preferably 5 to 1100 nm.

[Example 2] By changing the thickness of the base layer in the example construction, Example 1
We conducted a similar experiment to examine the effects of the pseudo gap. As an example, Fig. 3 shows Fe7aTaδC1 in the ferromagnetic film.
4 is used to show the influence of the thickness of the underlayer on the pseudo signal when Ni is inserted into the underlayer. As is clear from the figure,
The pseudo signal decreased as the thickness of the underlying layer increased, reached a minimum around 2 Onm, and then showed a tendency to increase again.

That is, when the thickness of the underlayer was from 1 to 1100 nm, the pseudo signal became 2 dB or less, and the influence of the pseudo gap was reduced. When other base materials were used, similar trends were generally observed, and the preferred base layer thickness was 1 to 1100 nm.

Here, the reason why the spurious signals increase when the underlayer thickness exceeds 20 nm is not necessarily clear, but the inventors speculate that it is related to the soft magnetic properties of the underlayer. There is. That is, if the underlayer is thick and the soft magnetic properties of the underlayer itself are not good, it is thought that the underlayer itself will act as a pseudo gap, resulting in the appearance of a pseudo signal.

〔Effect of the invention〕

As described in detail above, the magnetic head according to the present invention exhibits good recording and reproducing characteristics with few pseudo signals due to the influence of pseudo gaps. In other words, when this heat-resistant high saturation magnetic flux density film is used in a magnetic head of a magnetic recording device, especially a metal-in-gap type magnetic head, glass filling can be performed at a high temperature of 500°C or higher, and it has sufficient strength. It is possible to form a glass layer with

[Brief explanation of drawings]

Fig. 1 is a perspective view of the metal-in-gap type head of the present invention, Fig. 2 is a plan view showing the vicinity of the gap, and Fig. 3 is a graph showing the influence of the thickness of the underlayer on the pseudo signal output. be. 1...M n -Z n ferrite substrate, 2... Ferromagnetic metal diagram Otsui calculation, power 7 inputs

Claims (1)

[Claims] 1. Fe or Co as the main component, IVa, Va, VIa
A magnetic head in which a ferromagnetic film containing at least one element selected from group elements and at least one element selected from group IIIb, IVb, and Vb elements is formed on an oxide substrate. , Cr, Mn, Fe, Co, Ni, Cu, Zn between the ferromagnetic film and the oxide substrate.
, Si, Mo, and W, and at least a portion thereof is an oxide. 2. The magnetic head according to claim 1, wherein the ferromagnetic film is crystalline. 3. The magnetic head according to claim 1, wherein the underlayer has a thickness of 1 to 100 nm.