Observation of Magnetoresistance Effect in $n$ -Type Non-Degenerate Germanium With Co2Fe0.4Mn0.6Si Heusler Alloy Electrodes

Abstract

The local 3-terminal magnetoresistance properties of n-Ge/MgO/Co2Fe0.4Mn0.6Si lateral spin-valve devices were systematically investigated. In the spin extraction condition, clear steep voltage changes were successfully observed. We measured the bias voltage and temperature dependences of the spin resistance-area product. At a high bias voltage, the spin signal increased with increasing voltage, reaching a maximum value of $7.0~\Omega \mu \text{m}^{{{2}}}$ at $V_{{\rm {bias}}} = 663$ mV. The signal decreased with increasing temperature but was still observed up to 160 K.