Pr0.7Ca0.15Ba0.15MnO3 manganite: Electron paramagnetic resonance, conductivity and susceptibility

We present a systematic experimental study of single phase Pr0.7Ca0.15Ba0.15MnO3 manganites. Ferromagnetic insulating state is observed in wide temperature range between the Curie point and peak resistivity temperature. Two approaches for the analysis of the electron paramagnetic resonance (EPR) line-width (ΔH) were considered in details. The first approach is based on the proportionality between the temperature dependencies of resistivity and inverse ΔH. The second approach is based on the model where ΔH∝1/Tχdc (χdc is a static magnetic susceptibility). For the studied Pr0.7Ca0.15Ba0.15MnO3 manganites the resistivity, associated with the grain boundary scattering, follows Mott law; the EPR line-width, suggested to be an intrinsic property, is well described with polaron hopping model.

► Ferromagnetic insulating state is observed between Curie and peak resistivity points.
► FMI state is caused by dominating of super-exchange over double-exchange interaction.
► Resistivity follows Mott law and related to grain boundary scattering.
► EPR line-width are described by polaron model and associated with intrinsic property.