Publications by authors named "Sergey A Nikolaev"

Article Synopsis
  • Recent experiments demonstrated a significant increase in torques when a thin aluminum layer was added to a cobalt/platinum heterostructure, indicating a possible Rashba-like interaction at the Co/Al interface.
  • First-principles calculations revealed that this interaction leads to the emergence of a large helical orbital texture in the cobalt layer, driven by the orbital Rashba effect and the formation of surface states at the interface.
  • The study highlights that this orbital texture results in a nonequilibrium orbital accumulation, producing large current-induced torques and providing a theoretical foundation for using orbital transport phenomena in all-metallic magnetic systems with lighter elements.
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Magnetic Weyl semimetals have novel transport phenomena related to pairs of Weyl nodes in the band structure. Although the existence of Weyl fermions is expected in various oxides, the evidence of Weyl fermions in oxide materials remains elusive. Here we show direct quantum transport evidence of Weyl fermions in an epitaxial 4d ferromagnetic oxide SrRuO.

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The possibility of utilizing the rich spin-dependent properties of graphene has attracted much attention in the pursuit of spintronics advances. The promise of high-speed and low-energy-consumption devices motivates the search for layered structures that stabilize chiral spin textures such as topologically protected skyrmions. Here we demonstrate that chiral spin textures are induced at graphene/ferromagnetic metal interfaces.

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A complete set of the generalized drift-diffusion equations for a coupled charge and spin dynamics in ferromagnets in the presence of extrinsic spin-orbit coupling is derived from the quantum kinetic approach, covering major transport phenomena, such as the spin and anomalous Hall effects, spin swapping, spin precession, and relaxation processes. We argue that the spin swapping effect in ferromagnets is enhanced due to spin polarization, while the overall spin texture induced by the interplay of spin-orbital and spin precession effects displays a complex spatial dependence that can be exploited to generate torques and nucleate or propagate domain walls in centrosymmetric geometries without the use of external polarizers, as opposed to the conventional understanding of spin-orbit mediated torques.

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