Magnetic properties of R-T hydrides (Ho, Y)(6)Fe23H15

摘要

Magnetization measurements M(T, H, x) were performed on ferrimagnetic Ho6-xFe23H15 (x = 0.47 and 0.92) compounds in the 4.2-700 K temperature range (Curie temperature T-C similar to 600 K) in a magnetic field up to 5 5 kOe. In comparison to parent alloys, absorption of hydrogen leads to a decreasing compensation temperature, a strong increase of the magnetic moments of the compounds in the 200-400 K temperature range, and a higher Curie temperature. These results are analyzed within the frame of Herbst and Croat refined-Neel molecular field theory model, taking into account the increase of the iron magnetic moment and the weakening of the magnetic exchange coupling NHo-Fe as compared to their alloys values. The mean canting angle between rare earth and iron sublattices theta (theta less than or equal to 10degrees) is important for the yttrium-substituted compounds, particularly in the vicinity of compositions for which T-comp similar to 0 K. (C) 2003 Elsevier Science (USA). All rights reserved. [References: 15]