Free-standing ferromagnetic nano-membranes with thicknesses below 10 nm could effectively be used for spin selective filtering of electrons. Such membranes can work both as spin detectors in electron-spectroscopy, -microscopy and -diffraction as well as a source of spin polarized electrons. Theoretical studies and previous work has indicated that ferromagnetic membranes of a few nm have Sherman functions in the 30-60 % range and would provide an effective alternative to current spin detection technology. Here we demonstrate the fabrication of gold capped Co nano-membranes with a 2.6 nm Co layer and a total thickness below 10 nm. The membranes have a Sherman function S≈0.41 and a transmission of 3.7×10−2 for electron energies of 2 eV. The integration of such spin-filtering membranes in a hemispherical electron analyzer is shown to provide massively parallel detection capabilities and a "2-dimensional" figure of merit FOM2D = 67.2, the highest reported to date.
@article{arxiv.1709.03838,
title = {Free-standing magnetic nano-membranes for electron spin-filtering applications},
author = {T. Övergaard and B. M Wojek and M. Leandersson and H. Ohldag and S. Bonetti and T. Wiell and O. Tjernberg},
journal= {arXiv preprint arXiv:1709.03838},
year = {2017}
}