On the Field Emission from Ni, Gd, and EuS Evaporated on to Tungsten

Abstract

Tungsten tips coated with Ni, Gd and EuS are studied in a field electron microscope. Reproducible patterns are observed. The Gd-patterns show epitaxy with the W-substrate. With tempered tips the work functions are: Ni 5.1 ± 0.3 eV, Gd 3.2 ± 0.3 e V and EuS 3.1 ± 0.3eV. For the production of polarized electrons by field emission from materials with spin polarized bandstructure 1 - 4 the field emission from Gd, Ni and EuS is of interest.