Talk given by Dr. Jonas Fransson, Uppsala Universitet, Sweden Abstract: Magnetic exchange interactions between localized magnetic moments have been frequently studied for bulk materials over the years. By the advent of meso- and nanoscale structures that can be deviced in break junctions, semi-conducting heterostructures, and surfaces, questions about the non-equilibrium properties of such interactions arises. Especially, since those interactions have a direct impact on the excitation spectrum and, hence, on the transport properties. Here, I will present recent studies of magnetic exchange interactions between molecular magnets embedded in a tunnel junction, and show that these interactions can be very naturally partitioned into three types: (i) isotropic Heisenberg, (ii) anisotropic Ising, and (iii) anisotropic Dzyaloshinski-Moriya interactions. The properties of these interactions strongly depend on the back-ground electronic structure and I, moreover, demonstrate that they can be controlled using external electrical and thermal fields across the junction. The influence of the interactions on the spin excitation spectrum can be probed using, e.g., scanning tunneling microscopy techniques, and I present theoretical results pertaining to recent experimental observations. References: J. Fransson, J. Ren, and J. -X. Zhu, Electrical and Thermal Control of Magnetic Exchange Interactions, arXiv:1401.5592. J. Fransson, Dynamical exchange interactions between localized spins out of equilibrium, Phys. Rev. B, 82, 180411(R) (2010). P. Berggren and J. Fransson, Spin Inelastic Electron Tunneling Spectroscopy on Local Magnetic Moment Embedded in Josephson Junction, arXiv:1410.2844. J. Fransson, O. Eriksson, and A. V. Balatsky, Theory of spin-polarized scanning tunneling microscopy applied to local spins, Phys. Rev. B, 81, 115454 (2010). J. Fransson, Spin Inelastic Electron Tunneling Spectroscopy on Local Spin Adsorbed on Surface, Nano Lett. 9, 2414 (2009).

This event is part of the eventgroup INT Talks

Homepage
https://www.int.kit.edu/events.php

Speaker
Dr. Jonas Fransson, Uppsala Universitet

Uppsala Universitet
Materials Theory http://www.physics.uu.se/en/page/jonas-fransson

Organizer
Dr. Velimir Meded
Institut für Nanotechnologie
KIT
Karlsruhe
Mail: velimir meded ∂does-not-exist.kit edu

Targetgroup
Interested / Everyone