Ferromagnetic-antiferromagnetic state in manganites

Summary form only given. The interest in the perovskite Mn oxides is associated with a colossal magnetoresistance (CMR) that was observed in certain compounds near room temperature. Some authors think that CMR is bound up with magnetic two-phase ferromagnetic-antiferromagnetic state in these materials. We investigate the magnetic properties of La/sub 0.9/Sr/sub 0.1/MnO/sub 3/ single crystal, La/sub 0.7/A/sub 0.3/MnO/sub 3/ (A = Ca, Sr) ceramic and La/sub 0.1/Pr/sub 0.6/CaO/sub 3/MnO/sub 3/ and La/sub 0.84/Sr/sub 0.16/MnO/sub 3/ epitaxial films which testify to the ferromagnetic-antiferromagnetic state in these samples. All the samples have the temperature dependence of electrical resistivity of semiconducting type and CMR in the Curie point region.