Observation of uniaxial anisotropy along the [100] direction in crystalline Fe film

Abstract

We report an observation of uniaxial magnetic anisotropy along the [100] crystallographic direction in crystalline Fe film grown on Ge buffers deposited on a (001) GaAs substrate. As expected, planar Hall resistance (PHR) measurements reveal the presence of four in-plane magnetic easy axes, indicating the dominance of the cubic anisotropy in the film. However, systematic mapping of the PHR hysteresis loops observed during magnetization reversal at different field orientations shows that the easy axes along the and are not equivalent. Such breaking of the cubic symmetry can only be ascribed to the presence of uniaxial anisotropy along the direction of the Fe film. Analysis of the PHR data measured as a function of orientation of the applied magnetic field allowed us to quantify the magnitude of this uniaxial anisotropy field as Oe. Although this value is only 1.5% of cubic anisotropy field, its presence significantly changes the process of magnetization reversal, revealing the important role of the uniaxial anisotropy in Fe films. Breaking of the cubic symmetry in the Fe film deposited on a Ge buffer is surprising, and we discuss possible reason for this unexpected behavior.

Effect of low-temperature post-growth annealing on anisotropic strain in epitaxial Fe layers deposited on GaAs(001)

“…So we speculate that the observed reduction in the structural anisotropy will also cause a reduction of the uniaxial magnetic anisotropy of Fe film. Similar behavior was reported in previous studies where the interplay between uniaxial and cubic magnetic anisotropy of Fe layer is found to be affected by structural anisotropy resulting from Ge 29 and ZnSe 28 buffer layers deposited between the GaAs substrate and the Fe layer.…”

Role of Hydrogen Evolution during Epitaxial Electrodeposition of Fe on GaAs

“…The research on epitaxial Fe/GaAs structures is of ongoing interest for injection and detection of spin polarized electrons, [2][3][4] and the study of magnetism in reduced dimensions and at interfaces. 5,6 For a long time, molecular beam epitaxy (MBE), was the preferred method for the fabrication of Fe/GaAs structures. The influence of MBE deposition parameters on growth mode, interface formation, and the resulting properties of Fe/GaAs structures were studied and reviewed.…”

Magnetization reversal and interlayer exchange coupling in ferromagnetic metal/semiconductor Fe/GaMnAs hybrid bilayers

“…To quantify magnetic anisotropy, the angle-dependent PHR of magnetic layers can be analyzed on the basis of magnetic free energy, which is described by 25 , 46 – 48 where H C is the cubic anisotropy field, H U 1 is the well known uniaxial anisotropy field associated with the direction, H U 2 is the uniaxial anisotropy field associated with the [100] direction, φ H denotes the direction of the applied magnetic field, and φ M is the direction of magnetization in the film. The presence of H C , H U 1 , and H U 2 in a magnetic film can be identified from angular scans of PHR, as follows.…”

“…The presence of H C , H U 1 , and H U 2 in a magnetic film can be identified from angular scans of PHR, as follows. H C causes the hysteresis occurring at 〈110〉 directions, accommodating the stable PHR states around the 〈100〉 directions; H U 1 leads to differences between hysteresis widths across and (as well as between ) 43 and [110]); and the effect of H U 2 leads to an asymmetric shift of the hysteresis away from the 〈110〉 directions 47 , 48 .…”