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Negative magnetoresistance in La(0.6)Y(0.1)Ca(0.3)MnO(3): Evidence for charge localization governed by the Curie-Weiss law

S. Sergeenkov·H. Bougrine·M. Ausloos·A. Gilabert
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Abstract

Colossal negative magnetoresistance Δρ(T,B) observed in La(0.6)Y(0.1)Ca(0.3)MnO(3) at B=1T shows a nearly perfect symmetry around T_0=160K suggesting a universal field-induced transport mechanism in this material. Attributing this symmetry to strong magnetic fluctuations (triggered by the Y substitution and further enhanced by magnetic field, both above and below the field-dependent Curie temperature T_C(B)=T_0), the data are interpreted in terms of the nonthermal spin hopping and magnetization M dependent charge carrier localization scenario leading to Δρ(T,B)= -ρ_s(1-exp(-γM^2)) with M(T,B)=CB/|T-T_C|^n. The separate fits through all the data points above and below T_C yield C^{+}\simeq C^{-} and n^{+}\simeq n^{-}\simeq 1. The obtained results corroborate the importance of fluctuation effects in this material recently found (cond-mat/9812219) to dominate its magneto-thermopower behavior far beyond T_C.

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S. Sergeenkov, H. Bougrine, M. Ausloos, A. Gilabert. 1999-01-11. Negative magnetoresistance in La(0.6)Y(0.1)Ca(0.3)MnO(3): Evidence for charge localization governed by the Curie-Weiss law. https://doi.org/10.1134/1.568143

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