IEEE S.F. Bay Area Council e-GRID's
BayAreaTech

FRIDAY April 6, 2012
OEB Magnetics Chapter
Speaker: Prof. S. Van Dijken, Aalto University, Finland
Time: 11:00 AM
Cost: none
Place: Lawrence Berkeley Natl Lab, Berkeley
RSVP: Please respond by April 4 by email with name, company, to Peter Fischer, peter.fischer@ieee.org
Web: ewh.ieee.org/r6/oeb/mag

Spintronic devices currently rely on magnetic switching or controlled motion of domain walls by an external magnetic field or spin-polarized current.  Achieving the same degree of magnetic controllability using an electric field has potential advantages including enhanced functionality and low power consumption.  Here, an approach to electrically control local magnetic properties including the writing and erasure of regular ferromagnetic domain patterns and the motion of magnetic domain walls is presented.  The method is based on strain transfer from ferroelastic 90° stripe domains in ferroelectric BaTiO3 substrates to continuous magnetostrictive CoFe films with negligible magnetocrystalline anisotropy.  The dominance of magnetoelastic anisotropy in these multiferroic heterostructures causes full imprinting of the ferroelectric domain pattern into its ferromagnetic counterpart.  Furthermore, strong pinning of magnetic domain walls onto the narrow ferroelastic boundaries is demonstrated in the as-deposited state.  Optical polarization microscopy of both the ferroelectric and ferromagnetic domain structures reveals that domain correlations and strong inter-ferroic domain wall pinning are maintained in an applied electric field.  This leads to unprecedented electric-field control over the formation of ferromagnetic domains and lateral motion of magnetic domain walls, an accomplishment that opens the way to electric-field driven spintronics.