Magnetoresistance behavior in La{sub 0.7}Ca{sub x}MnO{sub 3} (x=0, 0.2, and 0.3) thin films
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400 (United States)
- Department of Electrical Engineering, North Carolina AT State University, Greensboro, North Carolina 27411 (United States)
A systematic investigation focused on the magnetoresistance (MR) behavior of La{sub 0.7}Ca{sub x}MnO{sub 3} (x=0, 0.2, and 0.3) thin films has been carried out. As indicated by the unit chemical formula, La{sub 0.7}Ca{sub x}MnO{sub 3} films with x=0.3, 0, and 0.2 represent external, internal, and mixed (external and internal) doped lanthanum manganite systems, respectively. Thin films of these materials have been grown {ital in situ} on (100) LaAlO{sub 3} substrates using a pulsed laser deposition technique. Microstructural characterization carried out on these films has shown that the films are smooth, free from impurities, and highly textured. Electrical resistance and magnetoresistance have been measured in the 10{endash}300 K range in magnetic field up to 5 T using a superconducting quantum interference device magnetometer. The MR ratios of La{sub 0.7}Ca{sub 0.3}MnO{sub 3} (x=0.3), La{sub 0.7}MnO{sub 3} (x=0), and La{sub 0.7}Ca{sub 0.2}MnO{sub 3} (x=0.2) films are found to be 825{percent}, 700{percent}, and 750{percent} at 200 K, 240 K, and 220 K, respectively. The variation in the insulator to metal transition and the MR ratio is attributed to internal chemical pressure and vacancy localization effects. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 659319
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 58, Issue 13; Other Information: PBD: Oct 1998
- Country of Publication:
- United States
- Language:
- English
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