Fyzikální ústav Akademie věd ČR

Institute and media

HiPER News, 3.6.2010.

Members of the HiPER community gathered...

IBM Cases studies, 5.3.2010.

IBM iDataPlex has a really...

Physical Review Focus, 4/9/ 2009.

A recently developed material...

Spin pumping in magnetic tunnel junctions and topological insulators: Theory and experiments

Seminar Thursday, 25/02/2010 10:00 - 11:00

Speakers: Branislav K. Nikolić, Dept. of Physics and Astronomy & Center for Spintronics and Biodetection, University of Delaware
Place: Fyzikální ústav AVČR, Cukrovarnická 10, Budova A - zasedací místnost
Organisers: Department of Spintronics and Nanoelectronics

The pursuit of the second-generation spintronics has been focused on harnessing coherent spin states and their dynamics in metals and semiconductors. The salient examples of phenomena involving both coherent spins and their time evolution is the spin-transfer torque and its reciprocal effect, termed spin pumping because it occurs in the absence on any bias voltage, where microwave driven precessing magnetization of a single ferromagnetic (FM) layer emits pure spin current into adjacent normal metal (N) layers. While it has been long considered that low transparent interfaces would completely screen the interfacial spin pumping effect, the recent surprising measurements of large voltage signals of the order of 1 µV in microwave driven FM/I/N and FM/I/FM tunnel junctions have attracted considerable attention. In this talk, I review these experimental results together with the nonequilibrium Green function (NEGF) approach to spin pumping we developed to explain the surprisingly large pumping voltage. In addition, this approach allows us to examine spin pumping into chiral spin-filtered edge states of recently discovered two-dimensional topological insulators, which can either substantially enhance the pumped pure spin current or convert it into transverse charge current as the electrically measurable signature of the inverse quantum spin Hall effect and topological phases of matter.

Attachments

Copyright © 2008-2010, Fyzikální ústav AV ČR, v. v. i.