Date/time: 3:30 PM, Fri, June 18 2010.
Room: Sumwalt 102

Speaker: Oleg Tretiakov, Texas A&M University.
http://www.pha.jhu.edu/~tretiak/

Title:
Minimization of Ohmic losses for domain-wall motion in ferromagnetic
nanowires

Abstract:
I will talk about current-induced domain-wall motion in thin
ferromagnetic wires. I will propose a novel way to move domain walls
with a resonant time-dependent current which dramatically decreases
the Ohmic losses in the wire and allows to drive the domain wall with
higher speed without burning the wire. For any domain wall velocity we
find the time dependence of the current needed to minimize the Ohmic
losses. Below a certain critical domain-wall velocity specified by the
parameters of the wire the minimal Ohmic losses are achieved by dc
current. Furthermore, I will identify the wire parameters for which
the losses reduction from its dc value is the most dramatic. I will
show that our approach gives a dramatic power reduction even in the
least favorable cases of the systems with very weak or very strong
non-adiabatic spin transfer torque (conventionally described by the
parameter beta), thus opening new doors for using materials with much
wider range of beta for spintronic devices.