Talk given by Prof. Jonas Fransson Department of Physics and Astronomy Uppsala University Uppsala, Sweden Abstract: The dynamics of spin systems have for long been studied using the Landau-Lifshitz-Gilbert equation of motion with parameters either put in by hand or estimated through various methods. While this phenomenological approach very well serves it purpose for macroscopic spins and microstructures, one can questions its value and applicability in atomistic approaches when addressing nano structured systems. Experiments performed on single magnetic atoms and molecules, moreover, show the importance of internal degrees of freedom which raise other questions about the validity of the semi-classical based methods. Stimulated by these reasons among others, the spin dynamics equations of motion were rederived for general non-equilibrium conditions, paying special attention to the exchange coupling between itinerant electrons and the localized spin, however, remaining within the Kondo-like coupling model. Using the resulting scheme, studies of the electronically mediated indirect exchange between the localized spins were undertaken in molecular systems. It is shown that the exchange coupling can be controlled by gate and bias voltages as well as temperature gradients, to transition the spin exchange between ferromagnetic to anti-ferromagnetic coupling. By subsequently addressing the transport properties of the junction, the two regimes demonstrate substantially different conductivities. Other examples of single spins in junctions will also be addressed, with special attention paid to its time-dependent properties.

This event is part of the eventgroup INT Talks

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

Speaker
Prof. Jonas Fransson

Uppsala University
http://katalog.uu.se/profile/?id=N96-1733

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

Targetgroup
Interested / Everyone