ISSN:
1090-6487
Keywords:
75.30.Vn
;
75.30.Kz
;
72.15.Rn
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract The colossal negative magnetoresistance Δρ observed in La0.6Y0.1Ca0.3MnO3 at B=1 T shows an unusual, nearly perfect symmetry (around the peak temperature T 0=160 K), suggestive of a Curie-Weiss-dominated transport mechanism in this material both above and below the field-dependent Curie temperature T C ≡ T 0. Attributing this symmetry to strong magnetic fluctuations below T C (which are triggered by the Y substitution and cause a “bootstrap” destruction of the ferromagnetic phase), the data are interpreted in terms of the nonthermal spin hopping and magnetization-dependent charge carrier localization scenario leading to $$\Delta \rho = - \rho _s (1 - e^{ - \gamma M^2 } )$$ , with the magnetization M(T,B)=CB/¦T−T C(B)¦ν. The separate fits through all the data points above and below T C yield C +≃2C − and ν+≃ν−≃1, in agreement with the predictions of the Landau mean-field theory.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1134/1.568143
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