The Experts below are selected from a list of 1458 Experts worldwide ranked by ideXlab platform
J Wunderlich - One of the best experts on this subject based on the ideXlab platform.
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optical spin transfer torque driven domain wall motion in a ferroMagnetic Semiconductor
Physical Review Letters, 2015Co-Authors: A J Ramsay, P E Roy, J A Haigh, R M Otxoa, A C Irvine, T Janda, R P Campion, B L Gallagher, J WunderlichAbstract:We demonstrate optical manipulation of the position of a domain wall in a Dilute Magnetic Semiconductor, GaMnAsP. Two main contributions are identified. First, photocarrier spin exerts a spin-transfer torque on the magnetization via the exchange interaction. The direction of the domain-wall motion can be controlled using the helicity of the laser. Second, the domain wall is attracted to the hot spot generated by the focused laser. Unlike Magnetic-field-driven domain-wall depinning, these mechanisms directly drive domain-wall motion, providing an optical tweezerlike ability to position and locally probe domain walls.
A X Gray - One of the best experts on this subject based on the ideXlab platform.
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bulk electronic structure of the Dilute Magnetic Semiconductor ga1 xmnxas through hard x ray angle resolved photoemission
Nature Materials, 2012Co-Authors: A X Gray, Jan Minar, Shigenori Ueda, P R Stone, Yoshiyuki Yamashita, J Fujii, J BraunAbstract:The origin of the magnetism in manganese-doped gallium arsenide has been the subject of much debate. Now, hard X-ray angle-resolved photoemission has been used to probe the electronic structure of this material and clarify the mechanism through which the magnetism arises.
A J Ramsay - One of the best experts on this subject based on the ideXlab platform.
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optical spin transfer torque driven domain wall motion in a ferroMagnetic Semiconductor
Physical Review Letters, 2015Co-Authors: A J Ramsay, P E Roy, J A Haigh, R M Otxoa, A C Irvine, T Janda, R P Campion, B L Gallagher, J WunderlichAbstract:We demonstrate optical manipulation of the position of a domain wall in a Dilute Magnetic Semiconductor, GaMnAsP. Two main contributions are identified. First, photocarrier spin exerts a spin-transfer torque on the magnetization via the exchange interaction. The direction of the domain-wall motion can be controlled using the helicity of the laser. Second, the domain wall is attracted to the hot spot generated by the focused laser. Unlike Magnetic-field-driven domain-wall depinning, these mechanisms directly drive domain-wall motion, providing an optical tweezerlike ability to position and locally probe domain walls.
Jairo Sinova - One of the best experts on this subject based on the ideXlab platform.
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intraband and interband spin orbit torques in noncentrosymmetric ferromagnets
Physical Review B, 2015Co-Authors: Huawei Gao, Liviu P Zârbo, Karel Výborný, Xuhui Wang, Ion Garate, Fatih Doǧan, A Cejchan, Jairo SinovaAbstract:Intraband and interband contributions to the current-driven spin-orbit torque in Magnetic materials lacking inversion symmetry are theoretically studied using the Kubo formula. In addition to the current-driven fieldlike torque ${\mathbf{T}}_{\mathrm{FL}}={\ensuremath{\tau}}_{\mathrm{FL}}\mathbf{m}\ifmmode\times\else\texttimes\fi{}{\mathbf{u}}_{\mathrm{so}}$ (${\mathbf{u}}_{\mathrm{so}}$ being a unit vector determined by the symmetry of the spin-orbit coupling), we explore the intrinsic contribution arising from impurity-independent interband transitions and producing an anti-damping-like torque of the form ${\mathbf{T}}_{\mathrm{DL}}={\ensuremath{\tau}}_{\mathrm{DL}}\mathbf{m}\ifmmode\times\else\texttimes\fi{}({\mathbf{u}}_{\mathrm{so}}\ifmmode\times\else\texttimes\fi{}\mathbf{m})$. Analytical expressions are obtained in the model case of a Magnetic Rashba two-dimensional electron gas, while numerical calculations have been performed on a Dilute Magnetic Semiconductor (Ga,Mn)As modeled by the Kohn-Luttinger Hamiltonian exchange coupled to the Mn moments. Parametric dependencies of the different torque components and similarities to the analytical results of the Rashba two-dimensional electron gas in the weak disorder limit are described.
Vijaysankar Kalappattil - One of the best experts on this subject based on the ideXlab platform.
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monolayer vanadium doped tungsten disulfide a room temperature Dilute Magnetic Semiconductor
Advanced Science, 2020Co-Authors: Fu Zhang, Boyang Zheng, Amritanand Sebastian, David H Olson, Mingzu Liu, Kazunori Fujisawa, Yen Thi Hai Pham, Valery Ortiz Jimenez, Vijaysankar KalappattilAbstract:Dilute Magnetic Semiconductors (DMS), achieved through substitutional doping of spin-polarized transition metals into semiconducting systems, enable experimental modulation of spin dynamics in ways that hold great promise for novel magneto-electric or magneto-optical devices, especially for two-dimensional (2D) systems such as transition metal dichalcogenides that accentuate interactions and activate valley degrees of freedom. Practical applications of 2D magnetism will likely require room-temperature operation, air stability, and (for Magnetic Semiconductors) the ability to achieve optimal doping levels without dopant aggregation. Here, room-temperature ferroMagnetic order obtained in semiconducting vanadium-doped tungsten disulfide monolayers produced by a reliable single-step film sulfidation method across an exceptionally wide range of vanadium concentrations, up to 12 at% with minimal dopant aggregation, is described. These monolayers develop p-type transport as a function of vanadium incorporation and rapidly reach ambipolarity. Ferromagnetism peaks at an intermediate vanadium concentration of ~2 at% and decreases for higher concentrations, which is consistent with quenching due to orbital hybridization at closer vanadium-vanadium spacings, as supported by transmission electron microscopy, magnetometry, and first-principles calculations. Room-temperature 2D-DMS provide a new component to expand the functional scope of van der Waals heterostructures and bring semiconducting Magnetic 2D heterostructures into the realm of practical application.