Magnetism of ultrathin films of Fe on Cu(100)

Abstract

Magnetism in ultrathin (1–10 ML) Fe films grown on Cu(100) has been studied by spin-polarized secondary electron emission spectroscopy. The variation of the magnetization with temperature and oxygen adsorption was investigated for various film thicknesses. The orientation of the magnetization for films between 5 and 6 ML thick switches reversibly between perpendicular (at low temperature) to in-plane (at high temperature). The switching transition temperature decreases with increasing film thickness, and is accompanied by a loss of long-range order over a range of 20–30 K. The transition is attributed to the temperature dependence of the perpendicular anisotropy. The effect of oxygen adsorption onto films with perpendicular remanence is to first suddenly turn the magnetization into the plane at a critical coverage, and then to kill the magnetization gradually with continued exposure. This indicates that the uniaxial surface anisotropy at the Fe-vacuum interface plays a major role in the magnetization of the film.

Temperature Dependence of the Surface Anisotropy of Fe Ultrathin Films on Cu(001)

“…It has been demonstrated for Fe films on Cu that the easy axis of magnetization can be switched by changing the film temperature [1][2][3]. The observed phenomenon is ascribed to temperature dependent magnetic anisotropy constants.…”

Magnetic Dead Layers Induced by Strain at fct Fe/Rh(001) Interface

“…1) Since this temperature is excessively high for magnetic ordering, the structure and magnetism of fcc Fe have been investigated in detail by using Fe films grown on the Cuð001Þ surface (a 0 ¼ 3:61 # A), which has a small lattice misfit with bulk fcc Fe. [2][3][4][5][6][7][8] On the other hand, it is known that in the Fe films grown epitaxially on a substrate with a large lattice misfit, a strain at the interface causes elastic deformation of the films, i.e., the Poisson effect, and leads to face-centered-tetragonal (fct) structure. The strain at the interface is released during the film growth by the change of the lattice constant or by the dislocation at the interface, which modifies the structural and magnetic phases of the Fe films.…”

Adsorbate and thermally induced spin reorientation transition in low-temperature-grown Fe/Cu(001)

“…Thermal treatment of the film can change the spin reorientation transition reversibly 40 as well as irreversibly. Reversible changes might arise from a pure temperature dependence of the anisotropy constants and will vanish after subsequent cooling of the film back to the starting temperature.…”