Investigations on phenomenological percolation assisted charge conduction mechanisms across LaFeO3 / La0.7Ca0.3MnO3 / SrTiO3 structure

Identification and understanding of charge conduction mechanisms for functional oxide based devices become necessary to implement any potential applications in spintronics. In this context, present communication deals with the phenomenological percolation model that governs the charge transport properties of chemically grown LaFeO3/La0.7Ca0.3MnO3/SrTiO3 (LFO/LCMO/STO) structure. Various structural aspects have been explored through X-ray diffraction (XRD) measurements. Temperature dependent resistivity behaviors [recorded under current in plane (CIP) mode and current perpendicular to plane (CPP) modes] under different applied magnetic fields have been understood using phenomenological percolation model. In this, phase separation scenario and disordered interface between LFO and LCMO layers have been identified to play effectively their interesting roles. Intrinsic and extrinsic contributions of MR have been identified for both the measurement geometries across LCMO thin film and LFO/LCMO interface. Isothermal magnetoresistance (MR) behaviors have been explained on the basis of universal model for MR isotherms which strongly support the role of electronic phase fluctuations and disordered LFO/LCMO interface. Present research findings demonstrate a practical approach to tune the resistive state of functional oxides by precisely controlling the interface between them. This also serves a better way to control the resistive state of functional oxide thin films by applying external magnetic field and to understand related charge conduction processes.