JPH0430404A - Magnetic laminated body - Google Patents

Abstract

PURPOSE:To obtain a suitable optical magnetic recording medium by laminating a thin film containing Cu and Au and a magnetic film. CONSTITUTION:The magnetic laminated body, which is suitable for an magnetooptical recording medium, is a laminated body or multilaminated body formed by laminating a Cu-Au alloy film, a thin film containing a Cu compound or alloy and an Au compound or alloy, a magnetic film compound of a transition metal consisting of Fe, Co and the like and rare-earth and the like. The composition of the above-mentioned magnetooptical recording medium is Cu1-xAux in the form of 0<X<1. As the thin film containing a Cu compound and an Au compound, there is a compound alloy of Pd, Pt and the like. The above-mentioned Cu-Au alloy film is ordinarily formed by a sputtering method, or by a vapor-deposition method. An Au compound or alloy is contained in the compositional ratio of Cu-Au atomic number (in the form of 0<X<1). The Cu-Au alloy film is formed by the ordinary sputtering method, or a vapor deposition method. The Cu-Au alloy film is formed into a laminated body composed of an Fe carrier film, an Fe transition metal film, and alloy films of rare-earth elements such as lanthanoids and actinoids.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic laminate, and particularly to a magneto-optical recording medium that utilizes the Kerr effect.

[Prior Art] Laminated bodies that have a magnetic film attached to them and have the property of changing the reflection angle of irradiated light are used in magneto-optical recording media, magneto-optical isolators, specific wavelength magnetic filters, magneto-optical switching devices, etc. There is. Among these, magneto-optical recording media are media that can record and reproduce information by irradiating the recording layer with an energy beam such as a laser beam, and can also be rewritten.
-There are ROMs, etc. The recording layer of these magneto-optical recording media has been developed to consist of magneto-optical recording media that have uniaxial magnetic anisotropy in the direction perpendicular to the film plane, and phase change recording media that produce an amorphous-crystalline phase change. has been done.

Magneto-optical recording media use a magnetic thin film that is easily magnetized in the direction perpendicular to the film surface (perpendicular magnetization film), and by creating reversal magnetic domains at arbitrary positions with a light beam, it is possible to change the direction of magnetization. Two pieces of information “1” and “0” are recorded. On the other hand, reading information recorded in this way utilizes the fact that when a laser beam is irradiated onto information corresponding to an inverted magnetic domain, the plane of polarization of transmitted or reflected light rotates due to the Faraday effect or Kerr effect. In order to make the playback device more compact, playback is performed by detecting the rotation angle of the polarization plane of reflected light (Kerr rotation angle) using the Kerr effect. In reproduction using the Kerr effect, various attempts have been made to increase the Kerr rotation angle (θK) in order to reduce reproduction read errors.

As a magneto-optical recording medium with a large Kerr rotation angle (θK),
At present, rare earth-transition metal-based amorphous thin films are the mainstream because they have no grain boundaries, have low media noise, and are easy to fabricate over a large area. These rare earth-transition metal based amorphous thin films include Gd-Co based, Tb-Fe based, Gd-
Various types, such as Fe-based and Tb-Fe-Co-based, have been reported.

[Problems to be Solved by the Invention] However, these amorphous thin films change significantly over time, have problems with thermal stability, corrosion resistance, etc., and have a short lifespan. Also,
In these rare earth-transition metal based amorphous thin films, the beam irradiated for recording is of a long wavelength such as 633 nm or 799 nm, so that the recording density of the recording layer becomes coarse.

At the beginning, a laminate of a single film of one element of CulAg1Au and a thin film of Fe or CO is formed at the light absorption edge of each of Cu, Ag, or Au (Cu is 560 nm, Ag is 310n
m, 500 nm for Au), it has been reported that θK was found to take the maximum value (in ■, 5ato,
H, Kida, T, Katayama Jpn, J
, Appl, Phys, 27 (1988)
L237;■T.

Katayarna, H, Awano, et, alo
Phys, Rev, Let66, (1988) 1
426). In other words, according to these reports, as shown in Figure 5, the single film thicknesses of Ag alone are 83, 34, and 9, and the thin films of Co are 25, 14, and 4. The optical absorption edge of Ag is 310 nm at θ of the laminate (surface is Co).
The maximum value of θ is obtained, which is more enhanced than that of a single Co film. In addition, as shown in Fig. 6, the single film thickness of Cu is 113, 171, and 245, and the film thickness of Fe is 70.
The θ of the laminate with 108 and 150 thin films (in the cases where the surface is CU and Fe, respectively) has a θ that is enhanced compared to the Fe single film at the optical absorption edge of Cu at 560 nm.
Take the maximum value of .

However, as far as this report is concerned, Cu.

The θ of a stacked body of a single film of Ag or Au and a thin film of Fe or Co takes an enhanced peak value at a shorter wavelength than that of a conventional rare earth-transition metal based amorphous thin film. Now, the construct Cu.

The maximum value is an enhanced peak only near the wavelength of the light absorption edge of Ag or Au, and the maximum value is near the wavelength of the light absorption edge of the constituent Cu, Ag or Au1.
It is limited to a few places.

The present invention has been made to eliminate the above-mentioned drawbacks, and provides a magnetic laminate in which θK is enhanced in the visible light region and can take a maximum value at any wavelength from 500 to 560 nm. The purpose is to

[Means for Solving the Problems] In order to achieve the above object, the magnetic laminate of the present invention is made of Cu.
It is formed by laminating a thin film containing Au and a magnetic film.

The thin film may have a composition expressed by 0<x<1 when expressed as Cu t-xA u W.

Further, the magnetic film may be a thin film containing rare earth and/or transition metal.

Furthermore, the magnetic laminate can be preferably used, for example, as a magneto-optical recording medium.

The preferred magnetic laminate of the present invention when used as a magneto-optical recording medium is an alloy film of Cu and Au, or a thin film containing a Cu compound or alloy and an Au compound or alloy, and a transition metal such as Fe5Co or a rare earth metal. It is also possible to form a laminate in which the laminate is further stacked. The composition of the alloy film of Cu and A'u is expressed as 0<x<1 when expressed as Cu 1- and Au.

In addition, as a thin film containing a Cu compound and an Au compound, C
Pd5Pt, Rh, Ru as u alloy or Cu compound
, Ti, Zr5HfSCr, Mn.

AI, Ga, In, 5bSSnSB i, Nb, O.

Compounds or alloys of PSS etc. and Cu, and Pd, Pt5Rh, Ru as Au alloys or compounds.

TiX Zr, HfS CrS MnS Al, GaS
In, Sb, Sn, B 1SNb, 0, PSS etc. and A
The compound or alloy with U is the composition ratio of the number of atoms of Cu and Au: Cu 1- x A u * (however, O<x<1)
It is included in The Cu and Au alloy film of the present invention can be easily manufactured by a normal sputtering method or vapor deposition method. That is, in order to obtain the desired composition ratio of Cu and Au, a composite target in which Cu and Au are arranged in an area ratio corresponding to the composition ratio is used, and a magnetron sputtering method or a bias voltage applied with a negative bias voltage of -20V to -150V is used. The alloy film can be manufactured by sputtering using a sputtering method or RF sputtering method, or by electron beam evaporation.

The lattice constant of the obtained alloy film is Cu(
Alternatively, the atomic number percent of Au) changes continuously from 3.62 for Cu alone to 4.08 for Au alone. As shown in Figure 2, the peak at θ of the CuAu alloy film corresponds very well to this lattice constant, and C
By using the atomic percentage of u (or Au) as a parameter, it can be continuously changed from the optical absorption edge of 500 nm of AU alone to the optical absorption edge of 560 nm of Cu alone.

A Cu-Au alloy film like this is made of Fe, Co.

A single film of Ni, or at least one of Fe, Co, and Ni and transition metals such as 5cSTi, V, Cr, and Mn, Y, La, CeXPr, Nd, and Pm.

Sm, EuXGd5TbXDy, Ho, E r, Tm5
Lanthanum series elements such as Yb and Lu, and Ac.

Th, Pa, U, Np, Pu, Am, Cm, Bk.

CfSE sSFm, a laminate with a large perpendicular magnetic anisotropy energy in θ by forming a laminate with thin films made of alloy films of various composition ratios of metals such as rare earth elements such as actinium series elements such as Md and No. can be obtained.

As shown in Fig. 3, the perpendicular magnetic anisotropy energy Ku of a thin film consisting of a Cu, -M uz alloy film and a Fe thin film is positive in the thin part, but becomes negative in the thin part. Become. Such a laminate can be suitably used as a magneto-optical element. Then, this laminate is taken as one unit,
By laminating multiple layers of this laminate, it is possible to obtain a magneto-optical recording medium having a large enhancement peak at θ with a beam of a desired wavelength, and it is possible to record with high density in a short wavelength region.

Further, the thin film made of the Cu compound and the Au compound of the present invention is laminated on the thin film made of the transition metal or rare earth metal shown in the section of the alloy film by a method such as reactive sputtering or reactive vapor deposition, and the atomic ratio of CuSAu is is ctz-xAux (however, O
The laminate is formed to have a desired composition ratio expressed by <x<1).

The magnetic laminate of the present invention is not limited to the above-mentioned magneto-optical recording medium, but also includes magneto-optical isolators, specific wavelength magnetic filters,
It can be applied to magneto-optical switch elements, etc.

[Example] Using a composite target with an area ratio of 1/2 of Cu and Au, an atomic ratio of 1=1 of CuAu (Cu o
, sA uo, s) with a thickness of 250 mm was formed. An Fe film having a thickness of 150 layers was laminated on this alloy film. As shown in FIG. 4, this laminate had a maximum value of θ with a beam having a wavelength of around 530 nm.

Furthermore, in the above embodiments, a laminate of an alloy film and an Fe film was described, but even if the laminate is a laminate of a Co film and a TbCo film,
, TbFeXFeCo.

A suitable magneto-optical recording medium can be obtained even if it is a laminate with a thin film made of TbFeCo or the like.

[Effects of the Invention] As is clear from the above description, the magnetic laminate of the present invention has a composition formula of Cu, -, Au, and O.
By changing the composition of Cu and Au as shown by <x<1, the peak of the Kerr rotation angle can be adjusted to
It can be continuously changed from 0 nm to 560 nm, which is the optical absorption edge of Cu. Therefore, a magnetic material having a peak Kerr rotation angle corresponding to a light beam of a desired wavelength can be obtained.

Moreover, the peak of the Kerr rotation angle can be shifted to the shorter wavelength side by selecting the composition, making it possible to manufacture high-density magneto-optical recording media and making equipment using them more compact. .

[Brief explanation of the drawing]

1, 2, 3 and 4 are diagrams showing the properties of the Cu, -xAu x alloy film according to an embodiment of the magnetic laminate of the present invention, and FIGS. 5 and 6 are It is a figure showing a conventional example.

Claims (4)

[Claims] 1. A magnetic laminate comprising a thin film containing Cu and Au and a magnetic film. 2. A first method characterized in that the thin film has a composition represented by 0<x<1 when expressed as Cu_1_-_xAu_x.
The magnetic laminate described in . 3. A magnetic laminate, wherein the magnetic film is a thin film containing rare earth and/or transition metal. 4. 4. The magnetic laminate according to item 1, 2, or 3, wherein the magnetic laminate is a magneto-optical recording medium.