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Effect of valence fluctuations in A sites on the transport properties of $La_{1-x}R_{x}MnO_{3}$ (R = Ce, Pr)

Philip, John and Kutty, TRN (1999) Effect of valence fluctuations in A sites on the transport properties of $La_{1-x}R_{x}MnO_{3}$ (R = Ce, Pr). In: Journal of Physics-Condensed Matter, 11 (43). pp. 8537-8546.

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La1-xRxMnO3 (R = Ce or Pr) exhibit valence fluctuations (R3+ and R4+) in the A sublattice of the ABO(3) perovskite structure. They also display a metal-insulator (M-I) transition and magnetoresistance effect even without the substitution of divalent cations. In La1-xCex MnO3, as Ce concentration increases (x = 0.05 to 0.6), the magnitude of resistivity decreases and the magnetic transition temperature, T-c, shifts towards higher temperature. The change in transport properties is attributed to the increase in Mn3+-Mn4+ pairs. The electronic and magnetic phase diagram is obtained for Lal(1-x)Ce(x)MnO(3) from the resistivity and dc susceptibility measurements over a broad range of temperature and concentrations. The thermopower and magnetoresistance are also measured for Lal(1-)Ce(x)MnO(3) for two x values (x = 0.3 and 0.6). The high temperature thermopower data fit to an adiabatic small polaron hopping mechanism.

Item Type: Journal Article
Publication: Journal of Physics-Condensed Matter
Publisher: Institute of Physics
Additional Information: Copyright of this article belongs to Institute of Physics.
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Date Deposited: 02 Jun 2009 07:08
Last Modified: 19 Sep 2010 05:25
URI: http://eprints.iisc.ac.in/id/eprint/18907

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