Excitation and spin-transport of hot holes in ballistic hole magnetic microscopy

A hybrid structure of a ferromagnetic Co/Au/Ni81Fe19 trilayer on p-type silicon is used to probe the excitation of electron-hole pairs in a ferromagnet during inelastic decay of hot electrons and the subsequent spin-dependent transport of the excited holes into the valence band of the p-type Si collector. The hole current is remarkably sensitive to magnetic fields, with a magnetocurrent of up to 250% and, unexpectedly, with a positive sign. We determine effective attenuation lengths and their magnetic field and bias voltage dependence