Tunable low-field magnetoresistance properties in (La0.7Ca0.3MnO3)1−x:(CeO2)x vertically aligned nanocomposite thin films

Abstract

Vertically aligned nanocomposite (VAN) (La0.7Ca0.3MnO3)1−x:(CeO2)x thin films have been deposited on SrTiO3 (001) substrates by pulsed laser deposition. Enhanced low-field magnetoresistance properties and tunable metal-insulator transition temperature (TMI) have been demonstrated via modulating the composition of (La0.7Ca0.3MnO3)1−x:(CeO2)x (x = 0, 0.05, 0.1, and 0.2). By increasing the atomic percentage of the CeO2 phase to 20%, a maximum magnetoresistance value of 51.8% can be achieved and the TMI value can be tuned from 113 K to 210 K. The enhanced magnetoresistance properties are attributed to the disordered grain boundary and tunneling structure generated by the insulating CeO2 phase. The change in the TMI value is attributed to the strain state in the La0.7Ca0.3MnO3 phase. Furthermore, high ferromagnetic anisotropy and enhanced magnetization have been demonstrated in the VAN system. This work demonstrates the power of multifunctionalities and property tuning in VAN thin films.