JPH0371403A - Ring head - Google Patents

Abstract

PURPOSE:To obtain a ring head having a high saturation magnetization characteristic and a good soft magnetic characteristic by forming a gap with a magnetic film having in-plane uniaxial magnetic anisotropy, specifying the angle of an axis of easy magnetization of the magnetic film to the gap and connecting a soft magnetic material to the magnetic film to form the closed magnetic circuit of a core. CONSTITUTION:The first core obtained by sandwiching an iron film 10 between ceramic substrates 12 and 12 and the second core consisting of a ferrite 14 are bound together integrally to constitute a head. The iron film 10 has the in-plane uniaxial magnetic anisotropy exhibiting a excellent soft magnetic characteristic only in the axis of easy magnetization in the film plane, the easy axis is strictly symmetrical to the gap 18 between both left and right sides and formed along the main magnetic path in the iron film 10 as shown by the arrow M. The dotted arrow K shows the magnetic path in the ferrite 14 or its magnetization direction. As a result, a high-saturation magnetization head having a good soft magnetic characteristic is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ring-shaped head for high-density magnetic recording.

[Prior Art] In recent magnetic recording technology, the development of higher coercivity of recording media is progressing, and in order to cope with this, high saturation magnetization is required of magnetic heads.

A conventional ring-type head has a core made of a soft magnetic material such as ferrite, permalloy, or sendust. The saturation magnetization of these magnetic materials is approximately 5kG, 7kG, and 10k, respectively.
It is G.

[Lesson 6 M that the invention seeks to solve] However, saturation magnetization of about 10 kG does not satisfy the above-mentioned requirement for high saturation magnetization. 20kG if possible
A head with a certain degree of saturation magnetization is desired. of course,
The head must also have good soft magnetic properties.

The present invention was made in view of these problems, and provides a ring-shaped nodlet with high saturation magnetization characteristics and good soft magnetic characteristics by using a new magnetic material and devising a head structure. The purpose is to

[Means for Solving the Problems] In order to achieve the above object, the ring type head of the present invention has a gap formed in the plane by a magnetic film having axial magnetic anisotropy, and an axis of easy magnetization of the magnetic film. is oriented in a predetermined direction with respect to the gap, and a soft magnetic material such as ferrite or sendust is connected to the magnetic film to form a closed magnetic path of the core.

A preferable direction of the axis of easy magnetization of the magnetic film is such that the axis of easy magnetization is symmetrical between both sides of the gear and the hub.

The material of the magnetic film is an iron film or an iron base material containing 1 at% of at least one of Sit At, Gap Ge, Be C+ N, or at least one of transition metal elements other than iron. A metal film containing the above.

Further, in order to obtain better high frequency characteristics, the magnetic film may have a laminated structure of the iron film or metal film and a ceramic layer.

[A magnetic film having uniaxial in-plane magnetic anisotropy exhibits excellent soft magnetic properties only in one specific direction (axis of easy magnetization) within the film plane. Its axis of easy magnetization is in a predetermined direction with respect to the gap,
For example, since the core is configured to be symmetrical on both sides, good soft magnetic properties can be obtained for the core as a whole.

As the material of such a magnetic film, iron or iron is used as a base material, and at least one of Sit AI+ Gap Get B+ C+ N, or at least one element of transition metal elements other than iron is contained at 1 at% or more. If a metal film is used, a head with particularly high saturation magnetization (approximately 20 kG) and good soft magnetic properties can be obtained.

Moreover, when such a laminated structure of an iron film or a metal film and a ceramic layer is used, eddy currents are difficult to flow even at high frequencies, wasteful current loss is reduced, and high frequency characteristics are improved.

[Example] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, the structure and operation of ring-shaped heads according to some embodiments will be explained with reference to FIGS. 1 to 7.

FIG. 1 shows the structure of a ring-shaped head according to a first embodiment. (a) is a top view, (a) is a front view, and (c) is a side view. This head consists of an iron film 10 and a ceramic substrate 1.
It has a structure in which a sandwich-type first core part sandwiched by 2.12 and a second core part made of ferrite 14 are integrally joined. Coil 16 is wound around the first core portion.

Iron GTO has in-plane uniaxial magnetic anisotropy that exhibits excellent soft magnetic properties only in one specific direction within the film plane (the axis of easy magnetization). This axis of easy magnetization is strictly symmetrical between both sides (left and right) with respect to the gap 18, and is preferably selected in a direction along the main magnetic path in the iron film 10 as shown by arrow M in FIG. Dotted arrows indicate magnetic paths or magnetization directions within the ferrite 14.

In addition, in FIG. 2, the ceramic substrate 12.12 and the coil 16 are omitted for convenience of explanation.

FIG. 3 shows the magnetization curve of the iron film 10. Curve 20 is a magnetization curve in the direction of the easy axis of magnetization, and as shown, it exhibits excellent soft magnetic properties with a small coercive force and a rapid rise. On the other hand, curve 22 is a magnetic curve in the direction perpendicular to the axis of easy magnetization, which has a large coercive force and a slow rise, and cannot be said to have good soft magnetic properties. In the other direction,
A magnetization curve having characteristics intermediate between these two curves 20 and 22 is obtained.

FIG. 4 compares the override characteristics of the head of this embodiment and a conventional ferrite head. This override characteristic is based on the magnetic tape with coercive force IEioooe (Oersted).
A 5 MHz signal was recorded, and then a 5 MHz signal was recorded, and the extent to which the I MHz signal appeared as noise during playback (that is, how much was left unerased) was investigated. In the figure, curve 24 is due to the groove in this embodiment, and curve 26 is due to the conventional ferrite groove, and the override characteristic of the former (head of this embodiment) is significantly greater than that of the latter (conventional head). It can be seen that it is excellent.

FIG. 5 is a diagram showing the head structure according to the second embodiment.
A) is a top view, (0 is a front view, and (C) is a side view.

The first and second core portions of this head are made of the same material as the first and second core portions of the head of the first embodiment, respectively. However, in the first embodiment, the tape sliding surface 19
was formed entirely by the first core part, whereas this second core part was formed entirely by the first core part.
In this embodiment, only the center portion of the tape sliding surface 19' is formed of the first core portion, and both ends of the tape sliding surface 19' are formed of the second core portion (ferrite 14'). therefore,
The first core portion constitutes only a small portion around the gap;
The ferrite in the second core occupies most of the head.

The coil 16' is also wound around the second core portion.

Corresponding to such a head structure, in an iron film 10" having in-plane uniaxial magnetic anisotropy, the axis of easy magnetization is located along the main magnetic path perpendicular to the gap 18", as shown by the arrow in FIG. As a result, the high saturation magnetization (approximately 21 kG) and excellent soft magnetic properties of the iron film 10' work effectively in this head, and the head of the first embodiment The same performance can be obtained.

FIG. 7 is a side view showing a thin film head structure according to a third embodiment. This head is designed to form a gap between an iron film 10" having in-plane uniaxial magnetic anisotropy and a permalloy 14", and the axis of easy magnetization within the iron film 10" is aligned with the magnetic field shown by arrow H. The direction of the road is selected.

Next, an example of a method for manufacturing the iron film 10 (10', 10'') and core used in the above embodiment will be explained with reference to FIGS. 8 to 13.

FIG. 8 shows the target and substrate configurations under sputtering conditions used to manufacture the iron film according to the example.

A feature of this spacing device is that target (iron) plates 22, 22 are placed on both sides of the substrate 20. Using such a facing target type Suba-Nota apparatus, a crystallized glass substrate (expansion coefficient α: 1.45×1) was prepared under the sputtering conditions shown in FIG.
0) Deposit an iron film on 20. After iron film formation, the 11th
According to the heat treatment conditions shown in the figure, in the furnace shown in Figure 9,
Heat treatment is performed while rotating the iron film (sample) 36 on the substrate 20 for a predetermined period of time. In FIG. 9, 34 is a heater, 38
40 is a rotary pump, 42 is an oil diffusion pump, and 44 is a liquid nitrogen tank.

As a result of the above sputtering and heat treatment, when a magnetic field is applied in the horizontal direction of the sputtering target in the iron film 36 (the magnetic field for magnetization measurement is in the direction of arrow J in FIG. 8).
In this case, a magnetization curve with excellent soft magnetic properties such as curve 20 in Fig. 3 is obtained, and in a direction perpendicular to the direction of magnetic field application (direction perpendicular to the target), a magnetization curve as shown in curve 20 in Fig. 3 is obtained. It will be done.

Figure 12 shows the holding force H of the iron film obtained by the above manufacturing method.
The film thickness dependence of c is shown. As shown in the figure, in the easy magnetization axis direction, the coercive force Hc becomes less than LOe when the film thickness is 3 μm or more.
Its minimum value is 0.550e.

FIG. 13 shows the manufacturing process of the throat core according to the example. First, in step (2), the substrate 50 is fabricated by the above iron film manufacturing method.
An iron film is formed on the surface of the iron film 50 on which the iron film is formed and the iron film 50' on which the iron film is not formed.
2.52 into spacks, crimped them together using a crimper 54, and heated them in N2 gas to make both 50.50
” is a negative body (56).Next, in step (2), this iron film 56 is sliced into pieces (58, 58) of a predetermined size, and a groove 60.EiO for installing a coil is formed in each piece. , mirror polishing is applied.Next, in step 2, a pair of iron film pieces (58, 58
) and weld them together with glass 62. Next, in step (2), the ferrite pieces 40 are joined, and in step (2), they are sliced to a predetermined thickness to complete one core main body 42. A core is completed by winding a coil around this main body 42.

In the above-mentioned embodiment, the magnetic film having in-plane l-axis magnetic anisotropy was made of an iron film, but Si
All Gal Get BI CI A magnetic film having similar in-plane back-axis magnetic anisotropy can also be obtained even if it is a metal film containing fat% or more of at least one type of element among N or at least one type of transition metal element other than iron. It is possible to configure Further, by forming a laminated structure of an iron film or the metal film described above and a ceramic layer, it is possible to reduce eddy current loss and improve high frequency characteristics. Further, instead of ferrite, it is also possible to use other soft magnetic materials such as sendust and permalloy.

[Effects of the Invention] By having the above-described configuration, the present invention provides the following effects.

According to the ring type head of claim 1, a magnetic film having uniaxial magnetic anisotropy is formed with a core to form a gap, the axis of easy magnetization is oriented in a predetermined direction, and this magnetic material is coated with a normal material such as ferrite. By connecting soft magnetic materials to form an integrated core,
A high saturation magnetization head with good soft magnetic properties can be obtained.

According to the ring type head of claim 2, by orienting the axis of easy magnetization of the magnetic film so that it is symmetrical between both sides with the gap as the center, a head that effectively exhibits the soft magnetic properties of the magnetic film can be obtained. .

According to the ring type head of claim 3, the material of the magnetic film having inner uniaxial magnetic anisotropy is iron or Sir All Gal Ges B with iron as the base material.

At least one element among C and N or at least one element among transition metals other than iron is added in fat.
% or more, a head with particularly high saturation magnetization can be obtained.

According to the ring-shaped head of claim 4, the iron film or metal film of claim 3 has a laminated structure with a ceramic layer.
A head with good high-frequency characteristics with less eddy current flow and less current loss can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of a ring-shaped hennode according to a first embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of the head in FIG. 1, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a diagram showing the override characteristics of the head according to the embodiment and the conventional head, and FIG. 5 is the structure of the ring-shaped head according to the second embodiment of the present invention. FIG. 6 is a diagram for explaining the operation of the head in FIG. 5. FIG. 7 is a diagram showing the structure of the ring-shaped thin film nozzle according to the third embodiment of the present invention. 9 is a diagram showing the main structure of a sputtering apparatus according to an embodiment of the present invention. FIG. 9 is a diagram showing the structure of a heat treatment apparatus according to an embodiment of the present invention. FIG. 10 is a diagram showing the sputtering conditions of the embodiment. FIG. 11 is a diagram showing the heat treatment conditions of the example. FIG. 12 is a diagram showing the film thickness dependence of the coercive force of the iron film according to the example. FIG. It is a figure showing the manufacturing process of (a) and (a). 10.10', 10"... Iron film, 14.14'... Ferrite, 14"... Permalloy 18.18'18"... Gap, 3
0... Crystal glass substrate, 32... Target, 34... Heater, 36... Sample (iron film), 38... Magnet, 40... Rotary pump, 42...Oil diffusion pump. C) Figure 1 Figure 2 Figure 5 Figure 8 Figure 30 Figure 10 (Suha 0 ivy row beef) (Heat-treated row beef) Figure C Figure 13

Claims (4)

[Claims] (1) A gap is formed with a magnetic film having in-plane uniaxial magnetic anisotropy, and the axis of easy magnetization of the magnetic film is oriented in a predetermined direction with respect to the gap, and a closed magnetic path of the core is formed using ferrite or A ring-shaped magnetic head characterized in that a soft magnetic material such as sendust is connected to the magnetic film. (2) The direction of the axis of easy magnetization of the magnetic film is symmetrical on both sides with the gap as the center.
Ring-shaped head as described. (3) The magnetic film is an iron film or Si using iron as a base material.
It is characterized by being made of a metal film containing 1 at% or more of at least one element among Al, Ga, Ge, B, C, and N, or at least one element among transition metal elements other than iron. A ring-shaped head according to claim 1. (4) The ring-shaped head according to claim 1, wherein the magnetic film has a laminated structure of the iron film or metal film according to claim 3 and a ceramic layer.