Tuning colossal magnetoresistance response at roomtemperature by La2/3+ySr1/3−yMn1−yCryO3

Abstract The special formula of La 2/3+ y Sr 1/3− y Mn 1− y Cr y O 3 with [Mn 3+ ]/([Mn 4+ ] + [Cr 3+ ]) ratio fixed at optimal proportion 2:1 was designed to tune colossal magnetoresistance (CMR) response around room temperature and test the possibility of ferromagnetic (FM) interaction of hetero-ionic coupling between Mn 3+ and Cr 3+ . The polycrystalline bulk samples were fabricated by the traditional solid-state reaction method. The structural, magnetic, electrical transports and magnetoresistance (MR) properties were investigated. An enhancement of CMR at room temperature with appropriate content y has been observed, meanwhile, substituting Cr for Mn in manganites shows inefficiency in lowering ferromagnetic–paramagnetic (FM–PM) transition temperature T c and metal–insulator (M–I) transition temperature T p . Experimental results indicate that there might exist a FM coupling between Mn 3+ and Cr 3+ .