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Zheng Lin(郑 琳) a) † , Lu Yi(鲁 毅) a) , Zhao Jian-Jun(赵建军) a) , Zhang Xiang-Qun(张向群) b) , Xing Ru(邢 茹) a) , Wu Hong-Ye(吴鸿业) a) , Jin Xiang(金 香) a) , Zhou Min(周 敏) a) , and Cheng Zhao-Hua(成昭华) b)

A polycrystalline sample Nd 0.5 Sr 0.3 Ca 0.2 MnO 3 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 0.5 Sr 0.3 Ca 0.2 MnO 3 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.