2006 APS March Meeting
Monday–Friday, March 13–17, 2006;
Baltimore, MD
Session Y22: Focus Session: Coupled Thin-Film Structures for Magnetic Recording
8:00 AM–10:24 AM,
Friday, March 17, 2006
Baltimore Convention Center
Room: 319
Sponsoring
Units:
GMAG FIAP
Chair: Axel Hoffmann, Argonne National Laboratory
Abstract ID: BAPS.2006.MAR.Y22.7
Abstract: Y22.00007 : Novel materials and media concepts for thermally assisted magnetic recording.
9:12 AM–9:48 AM
Preview Abstract
Abstract
Author:
Jan-Ulrich Thiele
(Hitachi Global Storage Technologies)
Magnetic media using materials with high uniaxial
magneto-crystalline
anisotropy, K$_{U}$, combined with a thermal assist to overcome
thermal
stability and write field limitations are widely seen as a potential
extension of current magnetic recording technology. Here we
present an
overview of recent work on adapting the thermo-magnetic
properties of
FePt-based high-K$_{U}$ materials for the requirements of such a
recording
system.
In [1] we recently proposed a novel media structure consisting of
two
exchange coupled films, a high anisotropy film like, e.g., FePt,
and a FeRh
film. At close to equiatomic compositions FeRh is an
antiferromagnet at low
temperatures. Interestingly, upon heating beyond a critical
temperature,
T$_{AF-FM}$, FeRh becomes ferromagnetic for temperatures
T$_{AF-FM}<$T$<$T$_{C}$. This opens interesting possibilities for
media
applications for thermally assisted recording: at a storage
temperature,
T$_{S}<$T$_{AF-FM}$, the magnetic information is stored in the
high-K$_{U}$ FePt layer. For writing at increased temperature,
T$_{AF-FM}<$T$_{W}<$T$_{C-FeRh}$, the FeRh becomes ferromagnetic,
effectively lowering K$_{U}$ and increasing the total magnetic
moment of the
bilayer, thus lowering its coercivity via an exchange spring
mechanism and
helping magnetization reversal at temperatures well below T$_{C}$
of the
FePt layer.
A related area of great interest is the magnetization dynamics
upon rapid
heating and cooling of FeRh films using \textit{fs}-laser
pump-probe techniques. First
results indicate that the AF-FM transition can be driven on a
timescale
below 1 \textit{ps} [2], yielding interesting insight into the
interaction of the spin,
electron and lattice subsystems.
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[1] J.-U. Thiele, S. Maat, E. E. Fullerton, Appl. Phys. Lett.
\textbf{82}
(2003) p2859-2861
\newline
[2] J.-U. Thiele, M. Buess, C. H. Back, Appl. Phys. Lett.
\textbf{85} (2004)
p2857-2859 and G. Ju \textit{et al.}, Phys. Rev. Lett.
\textbf{93} (2004) 197403.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2006.MAR.Y22.7