We show that the magnetization of a thin ferromagnetic (Ga,Mn)As layer can be modulated by picosecond acoustic pulses. In this approach a picosecond strain pulse injected into the structure induces a tilt of the magnetization vector M, followed by the precession of M around its equilibrium orientation. This effect can be understood in terms of changes in magnetocrystalline anisotropy induced by the pulse. A model where only one anisotropy constant is affected by the strain pulse provides a good description of the observed time-dependent response.
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http://dx.doi.org/10.1103/PhysRevLett.105.117204 | DOI Listing |
Nano Lett
May 2023
Ioffe Institute, St. Petersburg 194021, Russia.
Nat Nanotechnol
July 2022
Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan.
Electrical manipulation of the valley degree of freedom in transition metal dichalcogenides is central to developing valleytronics. Towards this end, ferromagnetic contacts, such as Ga(Mn)As and permalloy, have been exploited to inject spin-polarized carriers into transition metal dichalcogenides to realize valley-dependent polarization. However, these materials require either a high external magnetic field or complicated epitaxial growth steps, limiting their practical applications.
View Article and Find Full Text PDFJ Phys Condens Matter
August 2021
Ioffe Institute, 194021 St. Petersburg, Russia.
The paper deals with a study of the magnetic impurities spin relaxation in the diluted magnetic semiconductors above the Curie temperature. Systems with a high concentration of magnetic impurities where magnetic correlations take place were studied. The proposed theory assumes the main channel of the spin relaxation being the mobile carriers, which provide the indirect interactions of the magnetic impurities.
View Article and Find Full Text PDFSci Rep
September 2019
Department of Physics & Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea.
Strain perturbs atomic ordering in solids, with far-reaching consequences from an increased carrier mobility to localization in Si, stabilization of electric dipoles and nanomechanical transistor action in oxides, to the manipulation of spins without applying magnetic fields in n-GaAs. In GaMnAs, a carrier-mediated ferromagnetic semiconductor, relativistic spin-orbit interactions - highly strain-dependent magnetic interactions - play a crucial role in determining the magnetic anisotropy (MA) and anisotropic magnetoresistance (AMR). Strain modifies the MA and AMR in a nanomachined GaMnAs structure as measured by the anomalous Hall effect (AHE) and the planar Hall effect (PHE).
View Article and Find Full Text PDFSci Rep
September 2019
Department of Physics, University of Notre Dame, Notre Dame, Indiana, 46556, USA.
We report the observation of exchange bias in a ferromagnetic GaMnAsP/ GaMnAs bilayer, in which the easy axis in one layer is oriented out-of-plane, and in the other in-plane. Magnetization reversal in this system is explored using planar Hall effect (PHE) measurements under various initial conditions and with various field-cooling orientations. Our results show that the two magnetic layers are ferromagnetically exchange-coupled, and that such coupling results in pronounced exchange-bias-like shifts of magnetic hysteresis loops during reversal of in-plane magnetization.
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