Observation of antiferromagnetic interlayer exchange coupling in aGa1−xMnxAs/GaAs:Be<

Investigation of weak interlayer exchange coupling in GaMnAs/GaAs superlattices with insulating nonmagnetic spacers

“…A similar result has been reported in the case of trilayers, in which the AFM IEC was observed for a Be-doped spacer with d N ¼ 15 ML. 26 All of these data consistently provide evidence that the IEC in GaMnAs/GaAs systems is long-ranged compared to theoretical predictions. The apparent contradiction may be due to the difficulty of considering extended dimensions in theoretical calculations.…”

“…It was only very recently, however, that a robust AFM coupling between GaMnAs layers has been realized in experiments. [23][24][25][26] This desirable coupling was achieved when Be was explicitly introduced into the nonmagnetic spacer layers as a p-type dopant (typically at the level of p % 10 20 /cm 3 ). 23 Reversible switching between FM and AFM alignments was observed in both superlattice and trilayer configurations, which subsequently led to the realization of the GMR effect in electrical transport measurements in these systems.…”

“…23 Reversible switching between FM and AFM alignments was observed in both superlattice and trilayer configurations, which subsequently led to the realization of the GMR effect in electrical transport measurements in these systems. 25,26 The previous works demonstrated the importance of sufficient carrier density in the spacer layers for realizing robust AFM IEC. 23,25 In those works magnetization, polarized neutron reflectivity, and magnetotransport measurements were used to confirm the presence of the AFM IEC in the samples with Be-doped spacers.…”

Coexistence of magnetic domains with in-plane and out-of-plane anisotropy in a single GaMnAs film

“…This type of negative coercive field in magnetization reversal is often observed in ferromagnetic multilayer systems, in which the magnetic layers are coupled antiferromagnetically (AFM) with each other [24][25][26], as well as in submicron-width GaMnAs wires [27]. In case of multilayer systems, the magnetization of the layer can switch its direction when the external field becomes weaker than the AFM coupling field.…”

Invited Article: Polarization “Down Under”: The polarized time-of-flight neutron reflectometer PLATYPUS

“…7 The technique also has been utilized to study buried magnetic structures in exchange bias systems [8][9][10][11][12] and non-metallic systems, such as magnetic oxide thin films and semiconductors. [13][14][15][16][17] More recently, PNR has also been used as the source of additional scattering contrast in characterization of soft condensed matter solid/liquid interfaces with a magnetic underlayer. [18][19][20][21] For a more comprehensive review of the PNR technique and scientific examples, we refer to recent contributions in Ref.…”