MAGNETIC-ANISOTROPY OF SPUTTERED MEDIA INDUCED BY TEXTURED SUBSTRATE

Thin-film disks sputtered on the textured substrate can have a magnetization easy axis along the circumferential direction. The mechanism responsible for the induced magnetic anisotropy in CoCrTa films has been investigated. The in-plane anisotropic strain (epsilon-a) in CoCrTa films deposited on various thicknesses of Cr underlayer were calculated from the lattice constants of CoCrTa (101BAR1) in circumferential and radial directions measured by x-ray diffraction. Both the in-plane magnetic anisotropy energy (K-theta) and the in-plane anisotropic strain in the compressive side ( - epsilon-a) were observed to increase with the decrease of the thickness of the Cr underlayer. The corresponding calculated magnetostriction constant lambda was - 30 X 10(-6). This value is consistent with the magnetostriction constant of CoCrTa films measured by three points bending method, thus suggesting that the magnetic anisotropy in CoCrTa films is induced by the anisotropic strain through the inverse magnetostrictive effect.