MAGNETIC ANISOTROPIES IN RFE10-XCOXMO2 COMPOUNDS (R=DY, ER)

The effects of Co substitution on magnetic anisotropy and spin reorien tation phenomena have been investigated in the DyFe10-xCoxMo2 and ErFe 10-xCoMo2 (x=0 to 10) series in the temperature range from 4.2 to 300 K. X-ray diffraction patterns on aligned samples indicated that the ea sy direction of magnetization (EDM) of the DyFe10-xCoxMo2 series is al ong the c axis at room temperature for all values of x. The spin reori entations were observed for all samples in the DyFe10-xCoxMo2 series e xcept for x = 10, and the spin reorientation temperature, T(sr), decre ases with the increase of Co content x. The magnetic phase diagram of DyFe10-xCoxMo2 has been constructed. These results, together with the results from the YFe10-xCoxMo2 series, may lead to the conclusion that the anisotropy of Dy sublattice changes from planar to axial in the D yFe10-xCoxMo2 series with the increase of Co content. The EDM in the E rFe10-xCoxMo2 series was found to be nonaxial for 2 less-than-or-equal -to x less-than-or-equal-to 6 for all temperatures below T(c). For x<2 and x>6 the ErFe10-xCoxMo2 compounds exhibit an axial EDM at room tem perature, and spin reorientations occur at about 210 K for x = 8 and a t 140 K for x = 10. Since Er and Dy have opposite. sign of second-orde r Stevens factor, the above results of two systems are consistent.