The synthesis and magnetoresistance behavior of direct current magnetron sputtering thin film of La0.7Pb0.3MnO3-delta

The epitaxial La0.7Pb0.3MnO3-delta films are synthesized on (001), (110) an d (111) LaAlO3 single crystal substrates with the direct current magnetron sputtering technique. The influence of the deposition conditions (substrate temperature and orientation, and sputtering gas pressure) on the value of metal-semiconductor transition temperature are studied systematically. It i s concluded that the higher substrate temperature (greater than or equal to 820 degreesC) and the moderate gas pressure (7 similar to9 Pa) are benefic ial to the growth of high quality film and the entrance of oxygen. The magn etoresistance behavior of the as-grown films is strongly dependent, on the deposition conditions. The colossal magnetoresistance (CMR) at 235 K and 0. 6 T with 30% was observed in (110) orientated substrate under 9 Pa sputteri ng gas pressure and substrate temperature of 820 degreesC. (C) 2001 Elsevie r Science Ltd. AH rights reserved.