Structural transition induced enhancement of magnetization and magnetoresistance in epitaxial (Pr0.5Ba0.5MnO3)1−x:(CeO2)x vertically aligned thin films

Abstract

Epitaxial (Pr_0.5Ba_0.5MnO₃)_1−x:(CeO₂)_x (PBMO:CeO₂, x = 0, 10%, 20%, 35%, and 50% stands for the molar ratio of the CeO₂ secondary phase) vertically aligned nanocomposite (VAN) thin films were successfully fabricated on single crystalline (001) (La,Sr)(Al,Ta)O₃ substrates by pulsed laser deposition. With increasing x, a structural transition induced by the vertical strain from the CeO₂ secondary phase was observed at 20% ≤ x ≤ 35% by reciprocal space mapping. What's more, it is not only the enhancement of magnetoresistance that was observed but also the increasing magnetization. The maximum magnetization and magnetoresistance were achieved at x = 35%, which are almost 4.7 times (at 20 K) and 1.6 times (at 110 K) as high as those at x = 0%, respectively. Such great enhancement of magnetization can be attributed to the vertical strain induced structural transition. Our research indicates that the structural transition induced by the introduction of secondary phase CeO₂ plays an important role in improving the magnetic and transport properties of VAN thin films.