Studies of quenched disorder in La0.7Ca0.3MnO3-type CMR manganite system from magnetic, transport and positron annihilation spectroscopic measurements

The effects of quenched disorder on the structural, transport and magnetic properties of the La0.7Ca0.3MnO3-type colossal magnetoresistive (CMR) sample have been reported. Temperature-dependent resistivity and magnetization data of the quenched sample revealed interesting changes from those of the usual slow-cooled sample. This is attributed to the defects created in the quenched sample and confirmed from the X-ray diffraction (XRD) and positron annihilation spectroscopic studies.