Magneto-optical layer and magneto-optical recording medium
AssigneeTeijin Limited
InventorsYoshihiko Takeda, Tomokazu Umezawa, Kiyoshi Chiba
Life of this patent
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Abstract
A magneto-optical layer sensitive to a light with a short wavelength such as 400 to 550 nm and having a perpendicular magnetization can be deposited on a substrate at a room temperature. The magneto-optical layer is of a tertiary polycrystalline having a composition, for example, Co.sub. aPt.sub.b Ru.sub.c where 20.ltoreq.a.ltoreq.70, 10.ltoreq.b.ltoreq.70, 10.ltoreq.c.ltoreq.60 and a+b+c=100 or Co.sub.d Pt.sub.e Re.sub.f where d.ltoreq.80, 5.ltoreq.e, 5.ltoreq.f, 40.ltoreq.4d-5f and d+e+f=100, and has an easy magnetization axis perpendicular to the main surface of the layer.
Claims22
A magneto-optical layer of a polycrystalline tertiary or quaternary alloy, having an easy magnetization axis perpendicular to the surface of the magneto-optical layer and having a composition represented by one of the following:
- (i) Co.sub.a Pt.sub.b Ru.sub.c where 20.ltoreq.a.ltoreq.70, 10.ltoreq.b.ltoreq.70, 10.ltoreq.c.ltoreq.60 and a+b+c=100;
- (ii) Co.sub.d Pt.sub.e Re.sub.f where d.ltoreq.80, 5.ltoreq.e, 5.ltoreq.f, 40.ltoreq.4d-5f and d+e+f=100;
- (iii) Co.sub.g Pt.sub.h Re.sub.i Ru.sub.j where
- 15.ltoreq.g(2g+2h+j)/(2g+2h).ltoreq.80
- 5.ltoreq.h(2g+2h+j)/(2g+2h),
- 5.ltoreq.i+(j/2),
- 2g(2g+2h+j)/(2g+2h).ltoreq.3i+(3j/2),
- g+h+i+j=100, and
- ghij.noteq.0;
- (iv) Co.sub.k Pt.sub.l Q.sub.m where 30.ltoreq.k.ltoreq.75, 1.ltoreq.l.ltoreq.20 and k+l+m=100,
- (v) Co.sub.n Pt.sub.p Mo.sub.q where 50.ltoreq.n.ltoreq.85, 10.ltoreq.p, 3.ltoreq.q.ltoreq.20, n-q.gtoreq.40 and n+p+q=100;
- (vi) Co.sub.r Pt.sub.s Nb.sub.t where 60.ltoreq.r.ltoreq.80, 1.ltoreq.c.ltoreq.5, and r+s+t=100;
- and
- (vii) Co.sub.u Pt.sub.v Ta.sub.w wherein 40.ltoreq.u.ltoreq.80, 1.ltoreq.w.ltoreq.5, and u+v+w=100,
- wherein the magneto-optical layer has a perpendicular saturated magnetic field of 6 kOe or less.
Dependencies are inferred from the claim text.