MAGNETIC PROPERTIES OF ER2FE17-XSIX AND ER2FE17-XSIXC (X=0-3) COMPOUNDS PREPARED BY ARC MELTING

摘要

The crystal structure and magnetic properties of Er2Fe17-xSix and Er2Fe17-xSixC compounds were investigated. The results of the powder x-ray diffraction indicate that the Er2Fe17-xSix compounds crystallize in the hexagonal Th2Ni17-type structure and the Er2Fe17-xSixC compounds exhibit two phases of the hexagonal Th2Ni17-type structure and the rhombohedral Th2Zn17-type structure. The addition of Si results in a decrease in the lattice constants and the unit-cell volumes. The Curie temperature T-C of the Er2Fe17-xSix compounds is found to increase from 327 K for x = 0 to 485 K for x = 2.5 and then to decrease slightly with increasing x, whereas the T-C of their carbides Er2Fe17-xSixC undergoes a small enhancement with increasing Si concentration. An approximately linear decrease in the saturation magnetization with increasing x is observed when the non-magnetic Si atom is substituted for Fe. Spin reorientation transitions are observed in Er2Fe17-xSix and Er2Fe17-xSixC. Substitution of Si for Fe in Er2Fe17 leads to an increase in the uniaxial anisotropy of the Er sublattice; therefore, the spin reorientation temperature T-sr increases with increasing Si concentration. The introduction of carbon has a marked effect on shifting the T-sr towards higher temperatures. [References: 30]