Entropy Best Presentation Award at 5th International Electronic Conference on Entropy and Its Applications (ECEA-5)
14 January 2020
We are pleased to announce the winner of the Best Presentation Award that Entropy sponsored at the 5th International Electronic Conference on Entropy and Its Applications (ECEA-5), held from 18 to 30 November 2019.
“Spin Waves and Skyrmions in Magneto-Ferroelectric Superlattices: Theory and Simulation” by Hung T. Diep, Ildus F. Sharafullin
In this paper, we present the effects of Dzyaloshinskii–Moriya (DM) magnetoelectric coupling between ferroelectric and magnetic layers in a superlattice formed by alternate magnetic and ferroelectric films. Magnetic films are films consisting of a simple cubic lattice with Heisenberg spins interacting with each other via an exchange, J, and a DM interaction with the ferroelectric interface. Electrical polarizations of ±1 are assigned at simple cubic lattice sites in the ferroelectric films. We determined the ground-state (GS) spin configuration in the magnetic film. In zero field, the GS is periodically noncollinear (helical structure), and in an applied field H, perpendicular to the layers, it shows the existence of skyrmions at the interface. Using the Green’s function method, we studied the spin waves (SW) excited in a monolayer and also in a bilayer sandwiched between ferroelectric films in zero field. We show that the DM interaction strongly affects the long-wavelength SW mode. We also calculated the magnetization at low temperatures. Monte Carlo simulations were then used to calculate various physical quantities at finite temperatures, such as the critical temperature, the layer magnetization, and the layer polarization, as functions of magnetoelectric DM coupling and the applied magnetic field. Phase transition to the disordered phase was studied.