Hall-effect sign reversal inCaRuO3andSrRuO3thin films

Hall-effect measurements on epitaxial thin films of the metallic oxides ${\mathrm{CaRuO}}_3$ and ${\mathrm{SrRuO}}_3$ show a sign change from negative to positive as temperature is increased through ∼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. © 1996 The American Physical Society.