Abstract
The crystal structure and electric and magnetic properties of newly synthesized spinel manganites were investigated. CuNi0.5Mn1.5O4 had cubic spinel structure, and magnetoresistance effect like CMR in perovskite manganites was observed in this system for the first time. Judging from the calculation of effective-valency according to the result of Rietveld analysis, it was estimated that both of Mn3+ and Mn4+ are in octahedral site. This fact may be related with the reason why magnetoresistance effect appealed in this system.
