Dresden 2017 – wissenschaftliches Programm
MA 47.14: Vortrag
Donnerstag, 23. März 2017, 13:00–13:15, HSZ 04
Spin-torque and fluctuation-dissipation at FM-AFM tunnelling junctions — •Kei Yamamoto1,2, Georg Schwiete3,1, Olena Gomonay1,4, and Jairo Sinova1,5 — 1Institut für Physik, Johannes Gutenberg Universität, 55128 Mainz, Germany — 2Institute for Material Research, Tohoku University, Sendai 980-8577, Japan — 3Department of Physics and Astronomy and Center for Materials for Information Technology, The University of Alabama, Tuscaloosa, AL 35487 — 4National Technical University of Ukraine "KPI", 03056, Kyiv, Ukraine — 5Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 00 Praha 6, Czech Republic
Antiferromagnetic materials (AFM) are emerging as a promising candidate to be a fundamental building block of next generation spintronic devices. One of the highlights from recent experimental findings is their peculiar spin transport characteristics. In ferromagnetic-antiferromagnetic heterostructures, spin pumping measurements revealed a strong temperature dependence of AFM spin conductivity, while their spin-Hall magnetoresistance indicates that AFM can be as good a sink of spin as ferromagnetic materials (FM).
In this talk, I present a microscopic description of non-equilibrium spin transport through FM-AFM tunneling junctions. Employing path integral formulation of quantum statistical mechanics, one can derive formulas for spin torque, spin pumping and the power spectrum of spin current fluctuations at the junction in a single unified framework. As an application, the AFM magnetic moment fluctuation induced by a steady voltage/temperature bias is computed.