Structural, Electric and Magnetic Properties ...

The structural, electric and magnetic properties of PrSrCoO4 and Pr0.4Sr1.6CoO4 layered perovskites have been investigated. The Rietveld refinements of x-ray powder diffraction (XRD) patterns at room temperature indicate that the samples crystallize in K2NiF4-type structure with group symmetry I4/mmm. The specimens exhibit semi-conducting behavior. The electric mechanism of PrSrCoO4 obeys Arrhenius law and might be understood by small polaron models. On the other hand, the conduction of Pr0.4Sr1.6CoO4 follows two-dimensional variable range hopping model (2D-VRH). The magnetic properties of PrSrCoO4 show Curie-Weiss paramagnetic behavior within the studied range of temperature. While Pr0.4Sr1.6CoO4 exhibits two magnetic transitions; one is due to Griffiths phase and second because of a mixture between ferromagnetic (FM) and antiferromagnetic (AFM) transition. These transitions become broad and shifted towards low temperatures with increasing applied field. No complete FM state was observed for this higher content of Sr. Comparison with similar compounds of the same Sr content is also discussed.