Colossal Magnetoresistance of Polycrystalline (La_0.7Tb_0.3)_2/3Ca_l/3MnO₃ at Low Drive Field

The magnetic and electric properties of polycrystalline (La_0.7Tb_0.3)_2/3Ca_l/3MnO₃ were investigated. A spin glass-paramagnetic transition and metal-insulator transition were observed near 45K, and there exists continuous volume change in the range of measured temperature. At 60 K, a large anisotropic magnetostriction and a volume magnetostriction correspond to an isotropic colossal magnetoresistance (CMR) with the magnitude of more than 40% at an applied field of ±0.1 T. Our results demonstrate that the transition is of second-order in nature and CMR could be caused by spin-charge coupling in this compound.