Temperature dependence of magnetocrystalline anisotropy energy determined using Co-Cr-Ta single crystal thin films

The composition and temperature dependencies of uniaxial magnetocrystalline anisotropy constants K/sub u1/ and K/sub u2/ are investigated by torque magnetometry for (1010)-oriented Co/sub 96-x/Cr/sub x/Ta/sub 4/ single crystal thin films (x=8-19 at.%). The K/sub u1/ and the Ku/sub u2/ values of Co/sub 88/Cr/sub 8/Ta/sub 4/ are determined at 290 K to be 2.2/spl times/10/sup 6/ and 5.9/spl times/10/sup 5/ erg/cm3, 6.9/spl times/10/sup 5/ and 5.3/spl times/10/sup 4/ erg/cm/sup 3/, respectively, with increasing Cr concentration from 8 to 19 at.%. When the temperature is increased from 290 to 450 K, K/sub u1/ of Co/sub 88/Cr/sub 8/Ta/sub 4/ thin films decreases by 27% to 1.6/spl times/10/sup 6/ erg/cm/sup 3/. The temperature dependencies of K/sub u1/ and K/sub u2/ increase with increasing Cr content in Co-Cr-Ta films. The compositional and the temperature dependencies of K/sub u1/ and K/sub u2/ are related to the decrease in Curie temperature of Co-Cr-Ta material with increasing Cr concentration.