Magnetic Anisotropy in (Gd_1-xDy_x) Al₂Ternaries

Abstract

Measurements of the magnetization were carried out on the single crystal of (Gd 1- x Dy x )Al 2 ternaries with x =0.05, 0.1, 0.2 and 0.4 at 4.2 K. For all the compounds with 0.05 ≤ x ≤0.4, the easy direction of magnetization is along the [100] axis, the magnetization along the [110] axis increases gradually with increasing applied field and tends to saturate, whereas the magnetization along the [111] axis saturates after taking a sharp rise at a relatively low field. The observed magnetic moment indicates that the Gd and Dy ions have the moments for respective R 3+ free ions and those couple parallel with each other in the ternaries. The magnetization curves were analyzed in terms of the molecular field approximation including the cubic crystalline electric field. The theoretical curves are presented and are in reasonable agreement with the corresponding observed ones. Magnitude of the magnetic moment for Dy ion in the crystalline field is also discussed.