Study of colossal magnetoresistance material La-Sn-Mn-O epitaxial films

La-Sn-Mn-O (LSMO) thin films have been first epitaxially grown on (100) LaA lO3 single-crystal substrates by pulsed laser deposition (PLD). X-ray diffr action analyses showed that the structure of the film was perovskitelike wi th a uniaxial orientation. The temperature dependence of resistivity showed that an insulator-metal transition took place at the temperature T-p, whic h was a function of the film thickness and the tin concentration. The calcu lated magnetoresistance ratio MR% indicates that the maximum MR%,,, is as h igh as 10(3)% at 6 Tesla and 233 K, and there still exist 60% values of MR% at room temperature and 6 Tesla. All these results reveal that the present film is a novel colossal magnetoresistance material with the potential in the technological applications. The investigation of the magnetic propertie s indicated that the Curie temperature T-c systematically varied with the t in concentration. At low temperatures, the samples were spin-glass-like wit h the freezing temperature affected by the film thickness and the tin conce ntration. The study of the electronic structure showed that the tin concent ration had significant influence on the core level and structure of valence electron distribution. (C) 2000 Elsevier Science S.A. All rights reserved.