Strain induced ferromagnetism and large magnetoresistance of epitaxial La1.5Sr0.5CoMnO6 thin films

In this study, the structural, magnetic, and magneto-transport properties of La1.5Sr0.5CoMnO6 (LSCMO) thin films deposited on a SrTiO3 (001) substrate were investigated. A normal theta/2 theta x-ray diffraction, rocking curve, phi-scan, and reciprocal space mapping data showed that prepared LSCMO thin films are single phase and highly strained with epitaxial nature. Temperature vs. magnetization of LSCMO films exhibits strain-induced ferromagnetic ordering with T-C similar to 165 K. In contrast to the bulk samples, there was no exchange bias and canted type antiferromagnetic and spin glass behavior in films having thickness (t) <= 26 nm. Temperature dependent resistivity data were explained using Schnakenberg's model and the polaron hopping conduction process. The slope change in resistivity and magnetoresistance maximum (similar to 65%) around T-C indicates the existence of a weak double exchange mechanism between the mixed valence states of transition metal ions. Suppression of spin dependent scattering with the magnetic field is attributed for the large negative magnetoresistance in LSCMO films. Published by AIP Publishing