Dresden 2006 – scientific programme
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.28: Poster
Tuesday, March 28, 2006, 15:15–19:15, P1
Magnetic anisotropy of magnetite thin films — •Andreas Brandlmaier, Andrea Boger, Matthias Opel, Sebastian T. B. Goennenwein, and Rudolf Gross — Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meissner-Str. 8, 85748 Garching
Magnetite
(Fe3O4) is very promising for spintronic devices, since it
is predicted to be a half-metallic ferrimagnet with a
Curie-temperature TC=860 K. A detailed
understanding of the magnetic properties, in particular
magnetic anisotropy, therefore is of significant importance.
We have investigated epitaxial Fe3O4 thin films deposited by
pulsed laser deposition in Ar atmosphere at a substrate
temperature of 320∘C. The crystalline quality of
the films was checked with x-ray diffraction, and the magnetic
anisotropy was studied by means of ferromagnetic resonance (FMR)
at a microwave frequency of 9.3 GHz.
In (001) oriented films, we observe a cubic magnetic anisotropy
in the film plane, and a strong uniaxial magnetic anisotropy
perpendicular to it. At room temperature, the cubic anisotropy
field Kc1/M=0.6 mT is much smaller than the
effective uniaxial anisotropy field
Keff/M=430.0 mT, where the latter can be
quantitatively understood in terms of demagnetization. In
contrast, (111) oriented films exhibit uniaxial magnetic
anisotropy both in and out of plane. We discuss possible origins
of this unusual in-plane anisotropy. We furthermore address the
influence of specimen shape and temperature on the magnetic
properties.