JPH04249305A - Ferromagnetic laminated film - Google Patents

Abstract

PURPOSE:To obtain a Co-based laminated film whose saturation magnetization value is large by a method wherein an Mn layer is laminated on a face-centered cubic Co layer. CONSTITUTION:An Mn layer is laminated on a face-centered cubic (fcc) Co layer. In this case, both the Co layer and the Mn layer can be formed by using various film-formation methods such as an ion-beam sputtering method, an RF magnetron sputtering method, a vapor deposition method, a molecular-beam epitaxy method and the like. The fcc Co film can be obtained easily by forming a substratum body to becomes fcc Co when the Co film is formed, such as Pt, Pd or the like, on a substrate such as a quartz glass or the like and by growing a Co thin film on it. It is desirable that the film thickness of the Mn layer is at 3Angstrom or higher and at 200Angstrom or lower. In addition, the fcc Co film is not limited to one layer, and a plurality of layers may be laminated by using it as a fundamental unit. In this case, said Pt layer or the like may be laid in order to form the Co layer formed on the Mn layer as fcc.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferromagnetic laminated film suitable for application to high frequency magnetic devices and the like.

0002

2. Description of the Related Art The value of saturation magnetization is an important factor in the fields of high-frequency magnetic devices such as transformers and inductors, magnetic head materials, and permanent magnets. Co is one of the elements with a large value. The saturation magnetization value of bulk Co is 1450 emu/cc, and it is known that this value generally decreases when the film is made thinner. For example, it has already been reported that the value of saturation magnetization decreases in a laminated film of hcp Co (hexagonal Co) and Mn (J.
Appl. Phys. 57 (1985) 3651, J
．． Phys. F (Met. Phys.) 16 (1986
)93 etc.).

0003

[Problems to be Solved by the Invention] However, there is a strong demand for thinner films of high saturation magnetization materials, and a technology is desired that will not reduce the saturation magnetization value even when thinner films are made of Co-based materials. The present invention has been made in consideration of the above points, and an object of the present invention is to provide a Co-based laminated film having a large value of saturation magnetization. [Structure of the invention]

0004

[Means and effects for solving the problems] The present invention provides fc
This is a ferromagnetic laminated film characterized by laminating a Mn layer on a c Co (face-centered cubic Co) layer.

That is, the present inventors have discovered that when Mn is laminated on an fcc Co thin film, a saturation magnetization higher than that of bulk Co can be obtained. Although the cause is not clear, it is thought that Mn on the fcc Co film becomes ferromagnetic, increasing the saturation magnetization value of the laminated film.

[0006] Both the Co layer and the Mn layer can be formed by various film forming methods.
For example, ion beam sputtering method, RF magnetron sputtering method, vapor deposition method, molecular beam epitaxy (
(MBE) method.

[0007] The fcc Co film is formed by depositing Co such as Pt, Pd, or Cu on a substrate such as quartz glass.
It can be easily obtained by forming a base layer of cc Co and using this as a substrate to grow a Co thin film (FIG. 1). Furthermore, since the present invention does not depend on the method for producing FCC Co, it is not necessary to form a base layer as long as FCC Co can be directly formed (FIG. 2(a)).

Furthermore, the film is not limited to a single layer of fcc Co/Mn, but may be laminated in multiple layers using this as a basic unit. In this case, since the Co layer formed on the Mn layer is fcc, the above-mentioned Pt layer or the like may be interposed (Fig. 2(b)
)).

The thickness of the Mn layer according to the present invention is preferably 200 angstroms or less. In this range, the effect of increasing saturation magnetization by the Mn layer becomes significant. Although the Mn layer is effective even if it is extremely thin, it is preferably 3 angstroms or more.

0010

[Examples] Examples of the present invention will be described below. (Example 1)

[0011] As a substrate, a glass substrate with a Pt film provided as an underlayer (100 angstroms) was used,
After evacuating to a vacuum level of 5 x 10-7 torr in advance,
r gas was introduced until the partial pressure became 2.9 × 10-4 torr, and by ion beam sputtering method, fcc
A Co/Mn laminated film was manufactured.

[0012] The Co film thickness is 30 angstroms,
FIG. 1 shows the saturation magnetization when the Mn film thickness (tMn) is changed. As is clear from FIG. 3, the value of saturation magnetization increases by stacking Mn, and when tMn exceeds 200 angstroms, the value of saturation magnetization becomes comparable to that of bulk Co. (Example 2)

[0013] The base layer M is Pd (30 angstroms)
A film was formed under the same conditions as in Example 1 except that the Co film thickness (tCo) was 60 angstroms. In addition, the characteristics when the layer structure (Mn/fcc Co/M) was repeated multiple times were also investigated. The results are shown in FIG. It can be seen that the saturation magnetization value does not depend on the number of laminated layers and is superior to bulk Co in all cases. (Example 3) A film was formed under the same conditions as in Example 1 except that a GaAs substrate was used as the substrate, and the results are shown in FIG.

Although this example is a case in which there is no underlayer, as is clear from FIG. 3, it can be seen that, as in Example 1, a saturation magnetization larger than that of bulk Co is obtained by laminating Mn layers. .

[0015]

[Effects of the Invention] As explained above, according to the present invention, f
By laminating a Mn layer on a cc Co thin film, it is possible to obtain a ferromagnetic laminated film that can achieve saturation magnetization higher than that of bulk Co. Therefore, it is suitable for applications requiring high saturation magnetization, such as high frequency magnetic devices, magnetic heads, and permanent magnets.

[Brief explanation of the drawing]

[Fig. 1] A schematic cross-sectional view showing the layer structure of the ferromagnetic laminated film of the present invention

[Fig. 2] A schematic cross-sectional view showing the layer structure of the ferromagnetic laminated film of the present invention

[Figure 3] Characteristic diagram showing the magnetization characteristics of the ferromagnetic laminated film of the present invention

[Figure 4] Characteristic diagram showing the magnetization characteristics of the ferromagnetic laminated film of the present invention

[Figure 5] Characteristic diagram showing the magnetization characteristics of the ferromagnetic laminated film of the present invention

Claims (1)

[Claims] 1. A ferromagnetic laminated film characterized in that a Mn layer is laminated on a face-centered cubic Co layer.