Magnetic Transition from the Ferromagnetic to Spin Glass Like State in Eu_xYb_1−xAlloy

Abstract

The ac magnetic susceptibility, magnetization and electrical resistivity were measured for fcc Eu_xYb_1−x alloy (0≤x≤0.4). The x-temperature magnetic phase diagram was determined. Ferromagnetic state is observed for 0≤x<0.29. The paramagnetic to ferromagnetic state transition temperature, T_c, takes a maximum value, 31 K, near x=0.12. The ferromagnetic to spin glass like state transition temperature, T_t, suddenly appears at about x=0.17 and the ferromagnetic region disappears at about 10 K and x=0.29 (triple point). The paramagnetic to spin glass like state transition temperature, T_g, shows almost no concentration dependence in 0.29<x≤0.40. The spontaneous magnetization at 0 K obtained by an extrapolation holds the constant value, 7.6 μ_B/Eu atom, for x\lesssim0.1, and decreases linearly as x increases for x\gtrsim0.1. In the electrical resistivity data, the transition from the semimetallic to semiconducting state as x increases is found.