Abstract
We discuss the results of our experiments on tunnel devices based on (Ga,Mn)As structures. Those include p+-(Ga, Mn)As/n+-GaAs Esaki diodes and laterally defined narrow nanoconstrictions in (Ga,Mn)As epilayers. We found in those structures strong anisotropic magnetoresistance behaviour with features that could be attributed to the novel tunnelling anisotropic magnetoresistance effect. We argue however, that in case of nanoconstricted (Ga,Mn)As wires, some other physics has to be additionally employed to fully explain the observed effects.
Highlights
Ferromagnetic (Ga,Mn)As is a very good candidate for an injector of spin-polarized carriers into a non-magnetic semiconducting material because of its high spin polarization, as well as its high quality heterojunction with GaAs
A TAMR effect results in gradual changes in magnetoresistance, plotted normalized to its highest value, as the sample is rotated in an in-plane magnetic field
The results of our experiments show that one has to be careful while performing spin-valve experiments with (Ga, Mn)As/n+-GaAs Zener–Esaki devices, and be aware of the different types of anisotropies that can be present in devices and can influence the measured signal through the TAMR effect
Summary
MAX-Laboratory, Lund University, SE-221 00, Lund, Sweden. 2 Author to whom any correspondence should be addressed. We find that the observed spin-valve signal strongly depends on the underlying magnetic anisotropy of the magnetic layer. Samples with uniaxial anisotropy along the biaxial easy axes (types I and III) show sign reversal of the spin-valve signal upon rotation by 90◦ in an in-plane magnetic field, as for the samples investigated in [1]. This way a TAMR-related signal could be distinguished from a real spin-valve signal involving two-magnetic layers. We observe strong magnetoresistance effects with many features characteristic for the TAMR effect, namely sign reversal of the spin-valve signal upon rotation in an in-plane magnetic field. The size of the observed effect and more detailed analysis of the experimental data suggest, that some additional physics has to be employed to fully explain the behaviour of these nanostructures in a magnetic field
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
