Structural and electrical properties of Pr1−xSrxMnO3 (x=0.25, 0.3, 0.35 and 0.4) manganites

In this work, we have studied the structural features and electrical conductivity of the polycrystalline Pr1−xSrxMnO3 (x=0.25, 0.3, 0.35, 0.4) manganites. All the compounds have orthorhombic structure with space group Pbnm. The electrical resistivity of all the samples exhibits metal–insulator transition TMI for both H=0 T and H=8 T. At H=8 T, ρ (T) drops down considerably which indicates the existence of the CMR effect. The electron–phonon, electron–electron and electron–spin fluctuation interactions are effective to describe the resistivity behavior for temperature less than the metal–insulator transition (TMI). For temperatures, T>TMI, the insulating nature is discussed with a small polaron conduction (SPC) model. The resistivity of all the samples shows a field-dependent minimum at low temperature. The above is due to the Coulomb interaction between carriers strongly enhanced by disorder and Kondo-like spin dependent scattering.