Hall effect in strained La0.85Ba0.15MnO3 thin films -: art. no. 012403

Unique properties concerning the Curie temperature (T-C) of lightly doped La1-xBaxMnO3 thin films (0.05less than or equal toxless than or equal to0.2) possessing tensile strain from the substrate have been discovered. It was found that T-C increased significantly up to room temperature with decreasing film thickness. The purpose of this study was to employ Hall measurements to delineate the fundamental electric parameters associated with the observed enhancement in T-C. The T-C of a fabricated La0.85Ba0.15MnO3 epitaxial thin film increased from 258 K for a 729-nm-thick above room temperature (305 K) for 24-nm-thick film. The carrier density of films with various thickness was found to be almost constant (similar to6x10(20) cm(-3)) at 10 K, whereas the Hall mobility dramatically increased, from 5 cm(2)/V s for the 729-nm-thick film to 50 cm(2)/V s for the 24-nm-thick film. These results indicated that the enhancement in T-C was induced by an increase in carrier transfer resulting from lattice deformation of Mn-O-Mn networks rather than an increase in carrier density associated with ionic vacancy.