Hall-effect sign reversal in CaRuO3 and SrRuO3 thin films

Hall-effect measurements on epitaxial thin films of the metallic oxides CaRuO3 and SrRuO3 show a sign change from negative to positive-as temperature is increased through similar to 50 K. The presence of both signs together with the low- and high-temperature magnitudes of the Hall coefficients indicate that these materials are highly compensated metals. The sign change with temperature suggests that large regions of the Fermi surfaces in both materials have nearly zero band curvature. Comparisons to recent band-structure calculations are made.