Magnetoresistive behavior of Cr-doped manganites Pr_(0.44)Sr_(0.56)MnO_(3)

摘要

A complex structural, magnetic, and electric transport investigation shows that the Cr doping on Mn sites in the A-type antiferromagnet Pr_(0.44)Sr_(0.56)MnO_(3) provokes a nonuniform magnetic state with coexisting ferromagnetic and antiferromagnetic regions. Irrespective of the ratio of magnetic phases, the samples exhibit a nonmetallic behavior of resistivity and thermopower, pointing to the nanoscopic nature of the phase separation. A particularly large magnetoresistance encountered in a broad range of temperatures for samples with Cr doping of 4-6 supports such an idea.