Magnetic-polaron-driven magnetoresistance in the pyrochlore Lu2V2O7

The structural, magnetic, and transport properties of single-crystalline Lu2V2O7 are studied. Lu2V2O7 shows a ferromagnetic transition at TC=69.5K and a negative magnetoresistance (MR) as high as 50% at T2=75K with an applied field of 5T. Through various experiments, it is demonstrated that the mechanism for MR is not through double exchange, but through a polaron-mediated behavior similar to Tl2Mn2O7. This places Lu2V2O7 as the only other example of polaron-mediated MR among the pyrochlore oxides.