Magnetoresistance scaling in MBE-grown La{sub 0.7}Ca{sub 0.3}MnO{sub 3} thin films
- Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)
- Varian Research Center, 3075 Hansen Way, Palo Alto, California 94304 (United States)
We present a detailed analysis of magnetoresistance in tetragonal thin films of ferromagnetic La{sub 0.7}Ca{sub 0.3}MnO{sub {delta}} grown by atomic layer-by-layer molecular-beam epitaxy. The field and temperature dependence of the resistivity {rho} show an explicit dependence only on the fractional magnetization {ital M}/{ital M}{sub sat} and are consistent with a single approximate form {rho}{approx_equal}{rho}(0)exp[{minus}{ital C}({ital M}/{ital M}{sub sat}){sup 2}] for small and intermediate magnetization both above and below the Curie temperature ({ital T}{sub {ital C}}). The microscopic magnetization and susceptibility ({chi}) have been inferred from the low-field magnetoresistance above {ital T}{sub {ital C}} with {chi} following a Curie-Weiss form. We observe a sharp transition in the low-field ({ital H}) dependence of {rho} from quadratic ({proportional_to}{ital H}{sup 2}) above {ital T}{sub {ital C}} to linear ({proportional_to}{ital H}) below, consistent with a temperature-independent {rho}({ital M}). Finally we show that within a simple model this temperature-independent form for {rho} reproduces the behavior of the measured low-field sensitivity below {ital T}{sub {ital C}}. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 383197
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 54, Issue 10; Other Information: PBD: Sep 1996
- Country of Publication:
- United States
- Language:
- English
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