Ballistic electron magnetic microscopy on epitaxial spin valves

Abstract

The tip of a scanning tunnelling microscope has been used as an injector of hot electrons or hot holes into a spin-valve epitaxially grown on n-GaAsP. Spin dependent transport of injected- and hole excited electrons has been studied in an external magnetic field at room temperature. Significant variations in the collector current due to the spin dependent inelastic decay of the hot charge carriers have been measured for parallel and antiparallel configurations of the magnetization of the individual layers. We found magneto-current effects on the order of 600% and relative large transmission values compared to other BEMM-studies. In addition, we investigated the excitation of electron hole pairs with its subsequent electron transport in the spin-valve and found a magneto-current effect with positive sign.