Intrinsic inhomogeneities of low-doped lanthanum manganites in the paramagnetic temperature range
- Russian Academy of Sciences, Ural Branch, Institute of Metal Physics (Russian Federation)
The nature of the electrical resistivity for low-doped lanthanum manganites is elucidated. The electrical resistivity is described by the Efros-Shklovskii law (ln{rho} {radical} (T{sub 0}/T){sup -1/2}, where T{sub 0} {radical} 1/R{sub ls}) in the temperature range from T* Almost-Equal-To 300 K Almost-Equal-To T{sub C} (T{sub C} is the Curie temperature for conducting manganites) to their T{sub C} and is explained by the tunneling of carriers between localized states. The magnetoresistance is explained by a change in the size of localized states R{sub ls} in a magnetic field. The patterns of change in R{sub ls} with temperature and magnetic field strength determined from magnetotransport properties are satisfactorily described in the model of phase separation into small-radius metallic droplets in a paramagnetic matrix. The sizes R{sub ls} and their temperature dependence have been estimated through magnetic measurements. The results confirm the existence of a Griffith phase. The intrinsic inhomogeneities produced by thermodynamic phase separation determine the electrical resistivity and magnetoresistance of lanthanum manganites.
- OSTI ID:
- 22027942
- Journal Information:
- Journal of Experimental and Theoretical Physics, Vol. 114, Issue 1; Other Information: Copyright (c) 2012 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
- Country of Publication:
- United States
- Language:
- English
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