Anisotropy Of Ultrathin Fe Films Research Articles

Magnetic anisotropy of ultrathin Fe films grown on vicinal Si (111)

We have investigated magnetic anisotropy of ultrathin Fe films grown on vicinal Si (111) with 4° miscut towards [11-2] direction. Spin reorientation transition (SRT) from out-of-plane to in-plane proceeds in a wider thickness range than on flat substrates. Meanwhile, the easy axis of in-plane uniaxial magnetic anisotropy varies from [11-2] to [-110] with an intermediate state of approximate four-fold symmetry. The evolution of magnetic anisotropy is attributed to competition of surface magnetic anisotropy, first-order magnetocrystalline anisotropy, and step induced magnetic anisotropy from symmetry breaking and dipolar interactions.

Thickness-dependent magnetic anisotropy in ultrathinFe∕Co∕Cu(001)films

Using the full potential linearized augmented plane wave method, we have explored the thickness-dependent magnetic anisotropy of ultrathin Fe films with 1 ML Co underlayer on Cu(001) as well as other magnetic properties. It has been found that the magnetic moment of Co underlay is almost intact with increasing Fe film thickness. A similar trend has been observed in interior Fe layers, whereas the surface Fe magnetic moment is greatly enhanced compared to those in other layers. Through magnetic anisotropy calculations, we have found that the 1 ML Fe film on $\mathrm{Co}∕\mathrm{Cu}(001)$ has a perpendicular magnetic anisotropy, but the direction of magnetization changes to in-plane with increasing Fe coverage. It has been found that the spin-orbit interactions around the middle of Brillouin zone play an essential role in the spin reorientation transition.

Effect of substrate inclination on the magnetic anisotropy of ultrathin Fe films grown on Al2O3(0001)

We have investigated the effect of substrate inclination on the in-plane magnetic anisotropy of ultrathin Fe films grown on Al2O3(0001). For Fe films grown on flat Al2O3 substrates, no preferred direction of magnetization exists in the film plane due to the three equivalent epitaxial orientations of Fe(110) that form. However, for Fe grown on an inclined Al2O3 substrate, a uniaxial anisotropy appears that is parallel to the step edges. The anisotropy increases in magnitude with decreasing Fe thickness and growth temperature, and as the surface morphology changes from being rough to being smooth. We attribute the uniaxial anisotropy to the effective demagnetization field caused by the surface corrugation.

In situ study of in-plane magnetic anisotropy of ultrathin Fe films on Mo(1 1 0)

In-vacuum surface magneto-optical Kerr effect was used in conjunction with scanning tunneling microscopy and low-energy electron diffraction to study the in-plane magnetic anisotropy of ultra-thin Fe films on a vicinal Mo(110) substrate. A uniaxial anisotropy with the easy axis of magnetization along the [001] direction was found for this system down to nearly 2ML coverage, contradicting the results of recent theoretical calculations. The easy axis of a step-induced anisotropy was found to coincide with the surface step edges.

Magnetic phase transition and anisotropy of ultrathin Fe films grown on inclined Al2O3(0001) substrates

We investigated the magnetic properties of ultrathin Fe films grown on inclined Al2O3(0001) substrates at various growth temperatures. We report the evolution of the magnetism with Fe thickness tFe, growth temperature, and the effect of the inclination of the substrate orientation on the magnetic anisotropy. The films are superparamagnetic (tFe≈5 monolayer, ML), ferromagnetic (tFe>15 ML), or coexistent (tFe≈10 ML). The effect of inclination of the substrate is small in the superparamagnetic region and substantial in the ferromagnetic region. Fe thin films grown on the inclined substrate have a uniaxial magnetic anisotropy with the magnetic easy axis parallel to the step edge. This uniaxial magnetic anisotropy might be derived from the effective demagnetizing field due to the magnetic charge distribution at the corrugated surface. The strength of the uniaxial magnetic anisotropy decreases as the growth temperature increases. The dependence of the uniaxial magnetic anisotropy on growth temperature is caused by the change of growth mechanism, from smooth to rough with an increasing of growth temperature.

Study of in-plane magnetic anisotropy of ultrathin epitaxial Fe films grown on vicinal Mo(110) surface

In situ surface magneto-optical Kerr effect was used in conjunction with scanning tunneling microscopy and low-energy electron diffraction to study the in-plane magnetic anisotropy of ultrathin Fe films on a vicinal Mo(110) substrate. A uniaxial anisotropy with the easy axis of magnetization along the [001] direction was found for this system down to nearly 2 monolayers coverage, contradicting the results of recent theoretical calculations. The easy axis of a step-induced anisotropy coincides with the surface step edges.

Influence of Au segregation on the magnetic anisotropy of /(001)

Abstract We present a first-principles study of the magnetic anisotropy of ultrathin Fe films on Cu 3 Au (0 0 1) , to investigate the origin of the magnetic reorientation transition observed experimentally. Our results indicate a crucial role of the segregation of Au to the topmost surface at very low Fe thicknesses.

Perpendicular surface magnetic anisotropy in ultrathin epitaxial Fe films

The in situ surface magneto‐optic Kerr effect is used in conjunction with low‐energy electron diffraction and Auger characterizations to study the surface magnetic anisotropy of ultrathin Fe films for various epitaxial structures: face‐centered‐cubic (fcc) Fe(100) on Cu(100), fcc Fe(111) on Ru(0001), body‐centered‐tetragonal (bct) Fe(100) on Pd(100), and body‐centered‐cubic (bcc) Fe(100) on Au(100). All of these films exhibit a universal behavior of perpendicular spin orientations below a critical thickness of six monolayers (ML) or less, in spite of their structural differences, suggesting a surface electronic as opposed to geometric origin of the magnetic anisotropy. These films differ in their monolayer‐range magnetic properties due to interdiffusion and electronic interactions across the interface. Fe/Pd(100) and Fe/Au(100) exhibit submonolayer ferromagnetism and growth‐temperature dependent magnetic anisotropy, while <2 ML Fe/Ru(0001) lacks a ferromagnetic signature.