Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 73: Spincaloric Transport II (jointly with MA)

TT 73.3: Vortrag

Mittwoch, 18. März 2015, 15:30–15:45, H 0110

Magnonic spin currents in ferro- and antiferromagnetic materials — •Denise Hinzke, Severin Selzer, Ulrike Ritzmann, Frank Schlieckeiser, and Ulrich Nowak — Fachbereich Physik, Universität Konstanz, 78457 Konstanz

Recent experiments show that applied temperature gradients can excite magnonic spin currents in ferromagnetic (FM) materials [1]. These experiments have raised the question of the role of the relevant length scales for these spin currents. We perform atomistic spin model simulations using the Landau-Lifshitz-Gilbert equation to calculate these characteristic length scales of magnon propagation in the vicinity of temperatures gradients. Our numerical findings are supported by analytical descriptions [2]. Extending our investigations to antiferromagnetic (AFM) materials we determined the frequency dependent magnon propagation length and also simulate magnon propagation due to thermal excitation. One of our findings is that an applied temperature gradient can excite magnons still transporting heat even if the expected spin current is zero. Furthermore, it was shown that the maximisation of entropy drives FM domain walls (DW) in temperature gradients [3]. We extend our former numerical and analytical investigations of DW motion caused by magnon excitation to AFM materials and compare with FM materials [3]. We acknowledge financial support by the DFG through SFB 767 and through SPP "Spin Caloric Transport". [1] K. Uchida et al, Appl. Phys. Lett. 97, 122505 (2010) [2] U. Ritzmann et al. Phys. Rev. B 89, 024409 (2014) [3] D. Hinzke and U. Nowak, Phys. Rev. Lett. 107, 027205 (2011)