Mean-field analysis of ternary and quaternary rare earth-transition metal alloys for thermomagnetic recording

A mean-field model developed to analyze ternary (TbFeCo) and quaternary (TbGdFeCo, TbDyFeCo) alloys of interest in thermomagnetic recording is based on the localized mean-field theory and emphasizes the reduction of adjustable parameters. The experimental magnetization versus temperature curves are compared with the model predictions, and good agreement is obtained in all instances. The exchange parameters and atomic moment values obtained are consistent with the current understanding of these alloys. The possibility of including an itinerant model to account for the 3d transition-metal magnetic electrons is considered