Resistive and magnetoresistance behaviors of BiFeO3 incorporated La0.7Ca0.3MnO3 composites

Micronsized matrix of La0.7Ca0.3MnO3 (LCMO) was synthesized by solid state reaction route whereas BiFeO3 (BFO) nanoparticles were synthesized by sol-gel method. Different contents of BFO nanoparticles were incorporated into the micronsized LCMO matrix lattice to prepare their composites. X-ray diffraction (XRD) measurement was performed to understand the crystalline phases present in these composites. Structural investigation suggests the dual phase nature of all the composites (consist of LCMO and BFO phases). No extra phases other than two, LCMO and BFO phases, can be found in the XRD patterns. Transport and magneto-transport properties have been studied by recording the temperature and magnetic field dependent resistance of the composites. Resistivity behavior shows that all the composites exhibit metal to insulator transition at T-P which is highly sensitive to magnetic field and BFO content. The values of resistivity are also influenced by the applied magnetic field and BFO content in the composites. Since all three composites with different BFO contents (i.e. 0, 10 and 20%) exhibit low temperature resistivity minimum behavior, various theoretical models and mechanisms have been employed to understand the responsible charge conduction across the composite lattices. All composites exhibit negative magnetoresistance (MR) which has been discussed in detail on the basis of role of high resistive nanoparticles of BFO incorporated within the micronsized LCMO matrix.