Seminar 14th July 2017 11 a.m. FEE 176L/1107 Lecture Room
Static and Dynamical Properties of Antiferromagnetic Skyrmions in the Presence of Applied Current and Temperature
Dr Joseph Barker
Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Advanced Materials, Micromagnetics, Multi-physics, Multi-scale, Spintronics
- Ondrej Hovorka
Skyrmions are a type of spin texture which forms due to competing interactions. They can occur either as the true ground state of the system (a skyrmion lattice) or as particle like metastable excitations. It has been suggested that isolated particle like skyrmions could be used as information carriers in spintronic devices, leading to a lot of research in this area. In this work we have investigated whether metastable isolated skyrmions can exist in antiferromagnets. We study a bipartite chequer board like (G-type) antiferromagnet using numerical simulations. From a prepared initial state the isolated skyrmion is stable with the antiferromagnet. Applying spin transfer torque to the spin texture shows that the motion of the skyrmion can be very fast. Moreover, the skyrmion moves in a straight line and does not have the skyrmion Hall effect of the ferromagnetic counterpart. We also study some thermal properties showing the antiferromagnetic skyrmion to be more diffusive than in ferromagnetic systems. This study represents an initial foray into what could be a rich and interesting area due to the diverse nature of antiferromagnetic systems in nature. Many details were handled at a very phenomonological level and much more research is needed to understand many of the details following from this work.
Reference: J. Barker, O. Tretiakov, Phys. Rev. Lett. 116, 147203 (2016).