Critical behavior of Mo-doping La0.67Sr0.33Mn1−xMoxO3 perovskite system

Structure, magnetization, and specific heat have been investigated for the Mo-doping La0.67Sr0.33Mn1−xMoxO3 (x=0, 0.01, 0.02, 0.03, 0.04, 0.06) perovskite system. The ferromagnetic to paramagnetic transition temperature Tc is found to decrease from 369 K for x=0 to 361 K for x=0.06 with increasing Mo doping. According to a second-order phase transition model, the critical behavior near Tc are investigated systematically based on the specific heat data, and the critical exponents are determined to be α=0.04–0.06, β=0.35–0.41, γ=1.13–1.25. The values of the critical exponents are found to keep almost same magnitude for La0.67Sr0.33Mn1−xMoxO3 system. It is noticed that the value of the critical exponent β locates between the mean-field value (β=0.5) and the three-dimensional (3D) Ising model value (β=0.325), which suggests the coexistence of the short-range and long-range ferromagnetic orders around the critical temperature. The fundamental factors to dominate the magnitude of the critical exponent values for the perovskite-type manganese oxide systems have been discussed as well.