Magnetic ordering in amorphous Nd-Co, Gd-Co and Er-Co alloys

Authors

J.A. Gerber, University of Nebraska - Lincoln
D.J. Miller, University of Nebraska - Lincoln
David J. Sellmyer, University of Nebraska-LincolnFollow

Date of this Version

March 1978

Comments

Published by American Institute of Physics. J. Applied Physics 49, 1699 (1978). ©1978 American Institute of Physics. Permission to use. http://jap.aip.org/jap/.

Abstract

Previous studies of magnetism in amorphous rare earth–transition metal alloys have emphasized alloys rich in transition metal. We report here results on three rare earth rich amorphous alloys: Nd₆₄Co₃₆, Gd₆₅Co₃₅, and Er₆₅Co₃₅. Low field susceptibility, χ, was measured for T in the range 4.2 K≤T≤300 K and magnetization was measured for 1.3≤T≤200 K and applied fields, H, of 0≤H≤80 kOe. Curie-Weiss fits were made to high temperature χ (T) data to determine average effective moments and Weiss temperatures. Hysteresis loops were used to determine the coercive force and the ordering temperatures, T_c. The effective moments and saturation moments are compared with values calculated on the assumption of local moments on both the rare earth and Co ions. T_c values for Nd, Gd, and Er alloys are 38 K, 170 K, and 12 K, respectively. The data are consistent with a ferrimagnetic structure in Gd₆₅Co₃₅. Local random anisotropy appears to play an important role in the Nd-Co and the Er-Co alloys. Journal of Applied Physics is copyrighted by The American Institute of Physics.