La1-xBaxMnO3 thin films (0.05 <= x <= 0.2) with a tensile strain from substrate exhibit unusual film thickness dependence on the Curie temperature T-C. The T-C was found to increase up to room temperature with decreasing film thickness. In this study, the origin of the T-C enhancement is examined by performing Hall measurements. The carrier densities of various thick films were found to be almost constant value (similar to 6 x 10(20) cm(-3)) at 10 K, whereas Hall mobility drastically increased, from 5 cm(2)/V s for 729-nm thick film to 50 cm(2)/V s for 24-nm thick film. These results indicate that the T-C enhancement is induced by increase of carrier transfer due to lattice deformation of Mn-O-Mn networks. (c) 2004 Elsevier B.V. All rights reserved.