Effects of lattice distortion on the physical properties and surface morphology of magnetoresistive perovskite epitaxial films
- Department of Physics, California Institute of Technology, Pasadena, California 91125 (United States)
- Center for Space Microelectronics Technology, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)
The effects of lattice distortion on the physical properties of La{sub 0.7}Ca{sub 0.3}MnO{sub 3} epitaxial films are investigated. Our results suggest that larger substrate-induced lattice distortion gives rise to larger zero-field resistivity and larger negative magnetoresistance. Similar effects are also observed in samples of different thicknesses and on the same substrate material, with larger resistivity and magnetoresistance associated with thinner samples. In addition to x-ray diffraction spectroscopy, the degrees of lattice distortion in different samples are further verified by the surface topography taken with a low-temperature scanning tunneling microscope. Quantitative analyses of the transport properties suggest that the high-temperature (T{r_arrow}T{sub C}) colossal magnetoresistance (CMR) in the manganites is consistent with the conduction of lattice polarons induced by the Jahn{endash}Teller coupling, and that the low-temperature (T{lt}T{sub C}) magnetoresistance may be attributed to the magnetic domain wall scattering. In contrast, the absence of the Jahn{endash}Teller coupling and the large conductivity in La{sub 0.5}Ca{sub 0.5}CoO{sub 3} epitaxial films yield much smaller negative magnetoresistance, which may be attributed to disorder-spin scattering. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 496600
- Report Number(s):
- CONF-961141-; ISSN 0021-8979; TRN: 97:016285
- Journal Information:
- Journal of Applied Physics, Vol. 81, Issue 8; Conference: 41. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 12-15 Nov 1996; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
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