The TRR 227 kindly invites you to the joint Colloquium of the TRR 227 & the Dahlem Center for Complex Quantum Systems.
Speaker: Dr. Ulrike Ritzmann
Title: Magnon spin currents in ferro- and antiferromagnetic materials
In the last years, the investigation of generation and detection of magnonic spin currents has gained a lot of attention. Magnonic spin currents provide new alternatives for information transport and processing due to the absence of Joule heating and the reduced spin wave damping in magnetic insulators. In addition, the discovery of the spin Seebeck effect, which describes the excitation of magnon currents in the presence of temperature gradients, offer novel design concepts for waste heat discovery.
Using atomistic spin dynamics simulations, we have investigated the lengthscale of magnon propagation in magnetic materials, ranging from ferromagnets to antiferromagnets and ferrimagnets. We have shown that a magnon accumulation is generated by temperature gradients and we have studied their properties such as relevant lengthscales or the suppression effect by magnetic fields. Moreover, we have demonstrated that net spin currents can propagate through antiferromagnets, providing new possibilities for spintronic devices such as magnon spin valves. Recently, it has been shown that ultrafast spin currents driven by hot electrons excite high-frequency magnons in confined ferromagnetic layers. I will present our studies on spin dynamics in Fe|Cu|Fe-trilayer structures after laser excitation and the formation of standing waves in thin magnetic iron layers.
Furthermore, also magnetic textures such as domain walls or skyrmions are in the focus of many research activities to develop new concepts for data storage devices. In the last part of my talk, I will present our recent study on the motion of skyrmions and antiskyrmions in ultrathin magnetic films driven by spin-orbit torques. We have found new dynamical regimes as trochoidal motion and skyrmion-antiskyrmion pair generation.
Time & Location
Oct 16, 2018 | 04:15 PM - 05:15 PM
Lecture Hall 001 - Institute of Mathematics - Freie Universität Berlin
(Arnimallee 3, 14195 Berlin-Dahlem)