Pressure Effect on the Curie Temperature of Intermetallic Compounds Gd_1-xY_xCo₂

抄録

The pressure dependence of the magnetic transition temperature is studied for psudo-binary compounds (Gd_1-xY_x) Co₂ (x=0∼0. 7) by measuring the temperature variation of ac permeability (μ) under pressure up to ∼10 kbar. With increasing temperature, μ for x≤0. 4 decreases sharply at the magnetic transition temperature T_C and μ for x≥0. 5 makes a sharp peak just below the magnetic transition temperature T'_C. It was found that T_C and its pressure derivative (dT_C/dP) decrease almost linearly with x (x≤0. 4), but T'_C decreases and dT'_C/dP increases with x (x≥0. 5). The x dependence of T_C and dT_C/dP are discussed in terms of the model of exchange enhanced paramagnetsim and that of T'_C and dT'_C/dP on the basis of the experimental results of rapid increase of high field susceptibility and decrease of magnetic moment of Co with x, reflecting both effects of environment and metamagnetic properties on Co.