Anomalous Magnetotransport Properties ofR2Mo2O7near the Magnetic Phase Boundary

Abstract

The magnetic and transport properties of pyrochlore $R_2{\mathrm{Mo}}_2{\mathrm{O}}_7$ have been studied with variation of the rare earth ( $R$). The change of the mean ionic radius of $R$, which induces change of the lattice structure, determines the magnetic ground state (ferromagnetic or spin glass), and the magnetic phase boundary is correlated with the metal-insulator crossover. Furthermore, we found enhanced magnetoresistance and unusual residual anomalous Hall effect at low temperatures near the phase boundary, which can be attributed to the coexistence of both phases.