Magnetic anisotropies in RFe10−xCoxMo2 compounds (R=Dy, Er)

Abstract

The effects of Co substitution on magnetic anisotropy and spin reorientation phenomena have been investigated in the DyFe10−xCoxMo2 and ErFe10−xCoxMo2 (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 easy direction of magnetization (EDM) of the DyFe10−xCoxMo2 series is along the c axis at room temperature for all values of x. The spin reorientations were observed for all samples in the DyFe10−xCoxMo2 series except for x=10, and the spin reorientation temperature, Tsr, decreases 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 DyFe10−xCoxMo2 series with the increase of Co content. The EDM in the ErFe10−xCoxMo2 series was found to be nonaxial for 2≤x≤6 for all temperatures below Tc. For x<2 and x≳6 the ErFe10−xCoxMo2 compounds exhibit an axial EDM at room temperature, and spin reorientations occur at about 210 K for x=8 and at 140 K for x=10. Since Er and Dy have opposite sign of second-order Stevens factor, the above results of two systems are consistent.