Studies on Colossal Magnetoresistance Behaviour of Pr0.6Sr0.4MnO3/Pr0.5Ca0.5MnO3 Heterostructure Films

Abstract

Heterostructure bilayer thin films of Pr0.6Sr0.4MnO3/Pr0.5Ca0.5MnO3 were prepared by pulsed laser deposition, and the structural, magnetic and magnetotransport properties were studied, and the results were compared to that of Pr0.6Sr0.4MnO3 and Pr0.5Ca0.5MnO3 single-layer thin films. Structural analysis of the heterostructure reveals c-axis orientation for both the manganite layers. The heterostructure exhibits a higher metal-insulator transition temperature and a larger colossal magnetoresistance near room temperature than that of the single-layer counterparts. The electrical conduction above the metal-insulator transition could be explained within the realm of the adiabatic small polaron hopping mechanism, with lesser activation energies compared to the single-layer films. Magnetization measurements portray the presence of an unsaturated symmetric hysteresis loop for the heterostructure with the Curie temperature of ~270 K corresponding to the ferromagnetic ordering emanating from Pr0.6Sr0.4MnO3. These results could be qualitatively understood considering the combined effect of strain and ferromagnetic proximity of Pr0.6Sr0.4MnO3 with charge-ordered Pr0.5Ca0.5MnO3 manganite.