Giant magnetoimpedance near a metal–insulator transition: Study of Fe in a V2O3 matrix

We report microwave absorption measurements as a function of temperature (from 290 to 125 K) and magnetic field (from 0 to 0.3 T) in mm-thick parallelepipeds of sintered $V_2O_3$ and $V_2O_3$ containing micron-size Fe precipitates. As before, it turns out that near the metal–insulator (MI) transition, the loss exhibits a sharp peak as a function of temperature. On application of a magnetic field, the peak temperature for ($V_2O_3$ + Fe) changes by a few kelvin, causing a giant magnetoimpedance ( \approx 200% in 0.1 T field) in the neighborhood of the MI transition.