Magnetic anisotropy and magnetostriction of SmFe2 crystal

Abstract

Magnetic anisotropy and magnetostriction of SmFe2 crystal were studied. Crystals were group by a self-flux method using Sm as a flux. Magnetic anisotropy and magnetostriction were measured by means of a torque magnetometer and a new optical technique, respectively. SmFe2 shows a typical cubic anisotropy with anisotropy constants K-1 = -5.3 x 10(6) and K-2 = 1.9 x 10(6) erg/cm(3) at 300 K. Though the easy axis of magnetization is parallel to the [1 1 0] direction at low temperatures, it changes to the [1 1 1] direction at temperatures above 195 K. Magnetostriction constants were determined to be lambda(111) - 2010 x 10(-6), lambda(100) = -130 x 10(-6) and lambda(s) = -1258 x 10(-6) at 300 K. The magnetoelastic contribution Delta K-1 (similar to-8.8 x 10(6) erg/cm(3)) to the anisotropy constant seems to be larger than the intrinsic anisotropy constant K-1 (int) (similar to 3.5 x 10(6) erg/cm(3)) in SmFe2. If this is the case;easy axis of magnetization has been changed from the [1 0 0] direction (K-1 int > 0) to the [1 1 1] direction (effective anisotropy K-1 (eff) - K-1 int + Delta K-1 < 0) at 300 K by a large magnetoelastic contribution. (C) 1999 Elsevier Science B.V. All rights reserved.