Patent ID: 6017645
Filing Date: 2000-01-25
Classification: G11B,Y10S

Abstract:
A composite magnetooptic recording material comprising:a polycrystalline thin film deposited on a non-magnetic solid substrate, said thin film comprising microcrystals of about 10 to 30 nm in size and having the formula (I)Co.sub.x.sup.+2 M.sub.y M.sub.z 'Fe.sub.3-x-y-z.sup.+3 O.sub.4+t.sup.-2whereinM is a cation of at least one metal selected from the group consisting of Mn, Mo, V, W, Cr, Cu, Fe and rare earth elements;M' is a cation of at least one metal selected from the group consisting of Zn, Ti and Al;x is a number ranging from 0.4 to 2.2;y is a number ranging from 0.05 to 0.5;z is a number ranging from 0 to 0.5, such that the sum of (x+y+z) is less than 2.5; and t is a non-zero positive number,said thin film having a Faraday rotation of at least 1 degree per micron and a coercive field of at least 1000 Oe.