Patent ID: 6086993
Filing Date: 2000-07-11
Classification: G11B,Y10T

Abstract:
A magneto-optical recording medium capable of direct overwriting in a light intensity modulation mode, which comprises a substrate and a magnetic multilayer structure located on a surface side thereof, wherein:said magnetic multilayer structure comprises, in order from a substrate side thereof, a readout layer R.sub.01, a memory layer M.sub.1, an exchange force control layer C.sub.12 and a recording layer W.sub.2,each of said magnetic layers containing a rare earth element and a transition element,said readout layer R.sub.01, said memory layer M.sub.1, and said recording layer W.sub.2 having perpendicular magnetic anisotropy at room temperature, andadjacent magnetic layers being mutually coupled with exchange force,said magnetic multilayer structure satisfying the following conditions:Tc.sub.W2 >Tc.sub.M1t.sub.R01 /(t.sub.R01 +t.sub.M1)=0.3 to 0.6t.sub.R01 +t.sub.M1 =20 to 40 nmwhere Tc.sub.M1 is a curie temperature of said memory layer M.sub.1, Tc.sub.W2 is a Curie temperature of said recording layer W.sub.2, t.sub.R01 is a thickness of said readout layer R.sub.01, and t.sub.M1 is a thickness of said memory layer M.sub.1,said readout layer R.sub.01 containing gadolinium, iron, and cobalt as main components with the proviso that gadolinium is contained in an amount of 23 to 27 at %,said memory layer M.sub.1 containing terbium, iron, and cobalt as main components with the proviso that terbium is contained in an amount of 21 to 25 at %, andsaid exchange force control layer C.sub.12 containing gadolinium, iron, and cobalt as main components with the proviso that gadolinium is contained in an amount of 23 to 32 at %, and having a thickness of 30 nm or below.