STRUCTURE AND MAGNETIC-PROPERTIES OF R2FE15SI2CY (R=ND, SM, GD, AND ER)

A new series, R2Fe15Si2Cy (R=Nd, Sm, Gd, and Er), has been prepared by heating powders of their corresponding parents in CH4 gas at 700 degr ees C instead of about 500 degrees C. For these carbides, the carbon c oncentrations are close to the theoretical value of y=3 and the 2:17 s tructure is still retained up to 900 degrees C. The Curie temperatures are 620-650 K and the saturation magnetizations are 71-113 and 67-129 emu/g at T=300 and 80 K, respectively. The anisotropy fields are larg er than 70 and 110 kOe at T=300 and 80 K, respectively, for Sm2Fe15Si2 Cy. (C) 1997 American Institute of Physics.