Structure, Magnetic Properties and Magnetic Entropy Changes of Er2-xCexFe17 Compounds

摘要

Structure, magnetic properties and magnetic entropy change of Er{sub}(2-x)Ce{sub}xFe{sub}17 compounds have been studied in this paper. The results show that even crystal structure of the compounds is still the Th{sub}2Ni{sub}17-type hexagonal by Ce substituting for Er in Er{sub}2Fe{sub}17 compound, the exchange coupling coefficients have been changed between the Er and Fe sublattices, resulting in the Curie temperature of (Er,Ce){sub}2Fe{sub}17 compounds shifted into room temperature around by a small adjustment of the Ce content. The typical λ-shape (-△SM)-T curves of Er{sub}(2-x)Ce{sub}xFe{sub}17 compounds indicate that the phase transition near Curie temperature belongs to the second order one which conduces the compounds with larger magnetic entropy changes in a comparatively wider range of temperature. With the Ce concentration x between 0.05 and 0.10, the Er{sub}(2-x)Ce{sub}xFe{sub}17 compounds have a higher magnetic entropy changes and the maximal values are about 40～50% of the highest magnetic entropy changes of pure metal Gd in external field of 2 or 5T. Er{sub}(2-x)Ce{sub}xFe{sub}17 compounds are potential working media for magnetic refrigeration with their stable chemical properties, wide temperature range for magnetic refrigeration and low price.