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

Abstract

We report a detailed study of magnetization reversal in Fe/GaMnAs bilayers carried out by magnetotransport measurements. Specifically, we have used planar Hall resistance (PHR), which is highly sensitive to the direction of magnetization, and is therefore ideally suited for tracking magnetization as it reorients between successive easy axes in the two magnetic layers during reversal. These reorientations take place separately in the two magnetic layers, resulting in a series of different magnetization alignments (parallel or orthogonal) during reversal, providing a series of stable PHR states. Our results indicate that the magnetic anisotropy of the structure is dominated by cubic symmetry of both layers, showing two in-plane easy axes, but with significantly different energy barriers between the easy orientations. Importantly, a careful analysis of the PHR results has also revealed the presence of strong ferromagnetic interlayer exchange coupling (IEC) between the two magnetic layers, indicating that although magnetization reorients separately in each layer, this process is not independent, since the behavior of one layer is influenced by its adjacent magnetic neighbor. The ability to design and realize multiple PHR states, as observed in this investigation, shows promise for engineering Fe/GaMnAs bilayer structures for multinary magnetic memory devices and related multinary logic elements.

Effect of surface pinning on magnetic nanostuctures

“…These combination produces a rich variety of novel physical phenomena strikingly different from the individual constituents. The examples include large exchange bias [9,10], giant magneto-resistance [11], varied interlayer exchange coupling [12], unusual spin transport [13].…”

Enhanced Valley Polarization in WS2/LaMnO3 Heterostructure

“…[24,25] In addition, magnetic proximity effect from ferromagnetic substrates can yield an interfacial magnetic exchange field in monolayer TMD, offering an effective way for valley control. [32][33][34] A giant and tunable valley splitting has been predicted theoretically and realized experimentally in monolayer TMD and ferromagnetic substrate heterostructures. [28,29,35] More interestingly, a signature of interlayer exciton-magnon coupling has been observed in antiferromagnet-semiconductor van der Waals heterostructures.…”

Sign-reversal electron magnetization in Mn-doped semiconductor structures

“…A reversal of the magnetization by electrical or optical means may help construct the low-power spintronic devices eliminating the conventional magnetic switching method. The manipulation of magnetization by the electric field or current is well known both in nonmagnetic 1 and in magnetic semiconductors (e.g., GaMnAs) 2,3 and in hybrid semiconductor/ferromagnetic structures 4 .…”