Localized level hopping transport in La(Sr)CrO3

Abstract

High-temperature measurements have been performed on the electronically conducting oxide system ${\mathrm{La}}_{1-x}{\mathrm{Sr}}_x\mathrm{Cr}{\mathrm{O}}_3$ ($0<~x<~0.4$). The electrical conductivity displayed thermally activated temperature dependence between 300 and 1900 K with activation energies that varied between 0.11 and 0.19 eV. Seebeck coefficients measured over a similar temperature range showed little temperature dependence, an indication that the carrier mobility, rather than the carrier concentration, is thermally activated. The magnetic susceptibility was Curie-Weiss-like between 600 and 1100 K with an effective moment that decreased with an increase in strontium concentration. These results are shown to be consistent with transport by the adiabatic hopping of small polarons.