Quantum corrections to the conductivity in a perovskite oxide: A low-temperature study of LaNi1-xCoxO3 (0?x?0.75)

Rajeev, KP and Raychaudhuri, AK (1992) Quantum corrections to the conductivity in a perovskite oxide: A low-temperature study of LaNi1-xCoxO3 (0?x?0.75). In: Physical Review B: Condensed Matter, 46 (3). pp. 1309-1320.

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Abstract

In this paper we propose to study the evolution of the quantum corrections to the conductivity in an oxide system as we approach the metal-insulator (M-I) transition from the metallic side. We report here the measurement of the low-temperature (0.1 K<T<100 K) electrical conductivity of the perovskite-structure oxide system LaNi1-x CoxO3 (0?x?0.75). LaNiO3 is a metal and LaCoO3 is an insulator. The system is metallic for x?0.65. For all x, at low temperatures, the conductivity (?) rises with temperature (T). Below 2 K, ? follows a power-law behavior, ?(T)=?(0)+?Tm. For samples in the metallic regime, away from the metal-insulator transition (x?0.4), m?0.3�0.4. As the transition is approached [i.e., ?(0)?0], m increases rapidly; and at the transition [?(0)=0, xc?0.65], m?1. On the insulating side (x>0.65), m takes on large values and ?(0)=0. We explain the temperature dependence of ?(T), for T<2 K, on the metallic side (x?0.4), as arising predominantly from electron-electron interactions, taking into account the diffusion-channel contribution (which gives m=0.5) as well as the Cooper-channel contribution. In this regime, the correction to conductivity, ??(T), is a small fraction of ?(T). However, as the M-I transition is approached (x?xc), ??(T) starts to dominate ?(T) and the above theories fail to explain the observed ?(T).

Item Type:	Journal Article
Publication:	Physical Review B: Condensed Matter
Publisher:	The American Physical Society
Additional Information:	Copyright of this article belongs to The American Physical Society.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	30 May 2011 09:54
Last Modified:	30 May 2011 09:54
URI:	http://eprints.iisc.ac.in/id/eprint/37528

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