Structure, magnetism and electronic excitations of epitaxial gadolinium(0001) on tungsten(110)

Abstract

The growth habit and surface geometry of epitaxial Gd(0001) on W(110) were studied by Low-Energy Electron Diffraction (LEED) and Auger Electron Spectroscopy (AES). The magnetism and electronic excitations of the films (thickness d: 0 < d ≤ 1000 Å) were studied by the surface sensitive method of spin-polarized electron scattering. The bulk Curie temperature T_c,b was determined in situ, in UHV, by the magnetooptical Kerr effect. Clean Gd(0001) surfaces exhibit surface enhanced magnetic order resulting in T_c,s > T_c,b where T_c,s' T_c,b are the surface and bulk Curie temperatures. Spin-resolved photoemission spectroscopy with synchrotron radiation reveals magnetic surface reconstruction on Gd(0001), characterized by an essentially antiferromagnetic coupling between bulk- and surface-spins for temperatures T < T_c,b. Oxygen adsorption experiments show a strong dependence of oxide formation on the surface roughness.