Magnetic anisotropy and spin reorientation transitions in a Er2Fe14Si3 single crystal

Er2Fe14Si3 is a ferrimagnet (T C=474 K, M s=9.6 μB /f.u. at 2 K). In the ground state Er2Fe14Si3 is characterized by a surprisingly low magnetic anisotropy of a 'cone of easy axes' type with angle 30o between the magnetic moment and the c-axis. With increasing temperature the anisotropy enhances, the cone closes gradually and transforms by a second-order transition to the easy c-axis at 50 K. Then, at 116 K the 'axis to plane' spin reorientation occurs as a first-order phase transition. This transition is accompanied by a large anomaly in the specific heat very sensitive to applied magnetic field