Spin-polarized secondary electrons from a scanning tunneling microscope in field emission mode

A new technique has been developed which opens the way to magnetic imaging with nm resolution. A narrow electron beam produced with a scanning tunneling microscope operating in field emission mode impinges on the magnetic surface, and the spin polarization of the emitted secondary electrons is monitored. As a first result, a hysteresis loop from an Fe-based metallic glass shows that the low-energy secondary electrons excited with this technique are spin polarized.