Role of strain in magnetotransport properties of Pr0.67Sr0.33MnO3 thin films

We have studied the strain effects on the structural and magnetotransport properties of Pr0.67Sr0.33MnO3 (PSMO) thin films. The PSMO films were epitaxially grown on LaAlO3 (001), SrTiO3 (001), and NdGaO3 (110) substrates that induce biaxial compressive, tensile, and almost no strain in the films, respectively. The film thickness t, varied between 4-400 nm, was used as another controlling parameter of strain for each type of film. There exist two distinct thickness ranges with different thickness dependence of the magnetotransport properties. For t < 20 nm, the zero-field resistance peak temperature (T-p) and the high-field magnetoresistance (HFMR) properties are critically dependent on the thickness and the substrate. For t > 20 nm, the T-p and the HFMR ratio show weak t dependence. The results show evidence for the effects of the Jahn-Teller type distortion as well as disorders on the resistive transition temperature and the HFMR. (C) 2000 American Institute of Physics. [S0021-8979(00)06909-7].