Magnetic transition behavior of perovskite manganites Nd_0.5Sr_0.3Ca_0.2MnO₃ polycrystalline

A polycrystalline sample Nd_0.5Sr_0.3Ca_0.2MnO₃ is prepared by the conventional solid state reaction method. The structure and magnetic properties are investigated with x-ray diffraction (XRD) patterns, a superconducting quantum interference device (SQUID), and electron spin resonance (ESR). The sample is in single phase with the space group Pbnm symmetry. With the decrease of temperature, Nd_0.5Sr_0.3Ca_0.2MnO₃ undergoes three magnetic transitions: ferromagnetic transition at T_C ≈ 210 K, charge-ordering at T_CO ≈ 175 K, and antiferromagnetic transition at T_N=155 K. In addition, the activation energy E_a ≈ 52.78 meV can be extracted by curve fitting.