APS March Meeting 2016
Volume 61, Number 2
Monday–Friday, March 14–18, 2016;
Baltimore, Maryland
Session A18: Spin-Hall I
8:00 AM–11:00 AM,
Monday, March 14, 2016
Room: 317
Sponsoring
Units:
GMAG DMP FIAP
Chair: Arne Brataas, Norwegian University
Abstract ID: BAPS.2016.MAR.A18.4
Abstract: A18.00004 : Novel current driven domain wall dynamics in synthetic antiferromagnets
8:36 AM–9:12 AM
Preview Abstract
Abstract
Author:
See-Hun Yang
(IBM Almaden Research Center)
It was reported [1,2] that the domain walls in nanowires can be moved
efficiently by electrical currents by a new type of torque, chiral spin
torque (CST), the combination of spin Hall effect and Dzyaloshinskii-Moriya
interaction. Recently we domonstrated that ns-long current pulses can move
domain walls at extraordinarily high speeds (up to $\sim $750 m s$-$1) in
synthetic antiferromagnetic (SAF) nanowires that have almost zero net
magnetization [3], which is much more efficient compared with similar
nanowires in which the sub-layers are coupled ferromagnetically (SF). This
high speed is found to be due to a new type of powerful torque, exchange
coupling torque (ECT) that is directly proportional to the strength of the
antiferromagnetic exchange coupling between the two sub-layers, showing that
the ECT is effective only in SAF not in SF. Moreover, it is found that the
dependence of the wall velocity on the magnetic field applied along the
nanowire is non-monotonic. Most recently we predict an Walker-breakdown-like
domain wall precession in SAF nanowires in the presence of in-plane field
based on the model we develop, and this extraordinary precession has been
observed [4]. In this talk I will discuss this in details by showing a
unique characteristics of SAF sublayers' DW boost-and-drag mechanism along
with CST and ECT.
[1] Kwang-Su Ryu, Luc Thomas, See-Hun Yang, and Stuart Parkin, ``Chiral Spin
Torque at Magnetic Domain Walls'', Nature Nanotechnology 8, 527-533 (2013).
[2] Satoru Emori, Uwe Bauer, Sung-Min Ahn, Eduardo Martinez, and Geoffrey S.
D. Beach, ``Current-driven dynamics of chiral ferromagnetic domain walls'',
Nature Materials 12, 611-616 (2013).
[3] See-Hun Yang, Kwang-Su Ryu, and Stuart Parkin, ``Domain-wall velocities
of up to 750 m s$-$1 driven by exchange-coupling torque in synthetic
antiferromagnets'', Nature Nanotechnology 10, 221-226 (2015).
[4] See-Hun Yang, Chirag Garg, Paul Amari, Charles Rettner, and Stuart
Parkin, in preparation.
[5] Stuart Parkin and See-Hun Yang, ``Memory on the Racetrack'', Nature
Nanotechnology 10, 195-198 (2015).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2016.MAR.A18.4