Magnetization of thin Fe films on V(1 1 0) and Cr(1 1 0)

Abstract

The magnetization of thin Fe(1 1 0) films was measured by magneto-optical Kerr effect (MOKE) magnetometry and polarized neutron reflectometry (PNR). In order to further understand the influence of strain and roughness on the Fe magnetization different surfaces were prepared by evaporating Cr and V on V(1 1 0) single crystals by molecular beam epitaxy. By varying the growth temperature both smooth and faceted Cr and V surfaces were created. For the facets we obtained an up and down staircase structure with the ridges along the [0 0 1] direction that consisted approximately of subsequent (1 0 0) and (0 1 0) surfaces. For the thin Fe films that were evaporated on the smooth V(1 1 0) surface a relatively high reduction of the magnetization was obtained, independently of the film thickness. In terms of thickness the observed reduction is equivalent to an offset of Δ t=−(4.0±1.0) Å. A V layer evaporated on this structure does not further reduce the magnetization of the Fe. For comparison Fe evaporated on a smooth Cr film was investigated, and the reduction amounted to Δ t=−(1.4±0.4) Å. For thin Fe films on faceted V and Cr substrates Δ t=−(3.3±0.4) and −(2.6±0.3) Å were measured, respectively. For samples with a 2 Å Cr buffer layer between the V(1 1 0) single crystal and the Fe film we obtained Δ t=−(4.08±0.10) Å, a value which is close to the result obtained for the smooth V(1 1 0) substrate.