INVESTIGADORES
STEREN Laura Beatriz
congresos y reuniones científicas
Título:
- Lateral confinement effects on the magnetic domains arrangement of MnAs micrometric bars.
Autor/es:
FERNANDEZ BALDIS FTORTAROLO M., SIRENA M., STEREN L., VIDAL F., RACHE SALLES B., ETGENS V., EDDRIEF.
Lugar:
Buenos Aires
Reunión:
Conferencia; V At the Frontiers of Condensed Matter; 2010
Resumen:
One of the major challenges of spintronic
development nowadays is the capability of integrating semiconductors and
ferromagnetic materials in multifunctional devices. In this field, the MnAs
alloy is a promising material due to the facts that it presents ferromagnetism
until 314K and grows epitaxially on GaAs. The typical size of a
magneto-electronic device is 50-1000nm, so it is important to look at the
physical properties of MnAs in the nanoscale.
Previous studies performed on MnAs thin films indicate that the structural
and magnetic properties of theses materials differ from those of the bulk. A
magneto-structural phase coexistence is observed in a broad temperature range
just below the Curie temperature, formed by an hexagonal ferromagnetic phase
(alpha) and an orthorhombic (beta) paramagnetic phase. This phenomenon is
explained in terms of substrate-induced strains. The alpha and the beta phases
are organized in a regular pattern of stripes when the film is deposited onto
GaAs(100) while they are randomly organized when the film is grown on GaAs(111).
In this work we present a study of the magnetic properties of
MnAs(120nm)/GaAs(100) micrometric bars. Samples of different width and constant
length were fabricated by electron beam lithography. The bars were oriented
parallel and perpendicular to the hard-magnetic axis of the system, i.e.
c-axis. The magnetic imaging of the micrometric bars was made by magnetic force
microscopy between 240C and 110C. Our results indicate
that the alpha/beta phase coexistence and the magnetic domain arrangement
depend on the size and the orientation of the bars, while the alignment of the
stripes parallel to the axis is preserved in both orientation of confinement.