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

Abstract

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.

Spin-dependent hot electron transport and nanoscale magnetic imaging of metal/Si structures

“…and is found to decrease with electron energy, in accordance with previous studies [Haq et al, 2006]. In the case of Co/Cu/Co, the MC is decreasing from more than 200% just below 1.0 eV, to 50% at 2.0 eV.…”

Hot electron attenuation of direct and scattered carriers across an epitaxial Schottky interface

“…Transport studies using Ballistic Electron Emission Microscopy (BEEM) have a particular advantage in this regard as such processes can be easily studied using the same device structure as that employed to study direct hot electron scattering. In this work, we demonstrate hot electron scattering and attenuation in a model epitaxial Schottky interface of NiSi 2 /n-Si(111) using the different modes in BEEM [1,12,13]. We do this by changing the injection bias polarity of the scanning tunneling microscope (STM) tip that is used in the BEEM, such that we study hot electron attenuation of both the direct and scattered electrons by injecting hot electrons and hot holes respectively.…”

Spin-filter scanniing tunneliing microscopy : a novel technique for the analysis of spin polarization on magnetic surfaces and spintronic devices

“…Its usefulness range from the application as an imaging technique for magnetism in thin films [92] and nanostructures [95], acquisition of nanoscale hysteresis loops [96], up to studying fundamental processes of spin-dependent hot-electron transmission [93,94]. Regarding the latter it is worth noticing that by using p-type semiconductor substrates it has also been possible to study spin-dependent transport of hot holes in a variant technique called ballistic hole magnetic microscopy (BHMM) [97,98,99,100]. The complementary study of hot-hole transport gives insight into the spin dependence of electron-hole scattering processes in magnetic thin films [101].…”