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Atomically Engineered Mn-Pd-Fe
Heterostructures: Exchange Anisotropy and Advanced
Characterization with Electron, Photon and Neutron
Probes
Funding: DoE/BES (07/15/02 - 07/14/06)
Project summary:
This research is directed at the fabrication and advanced
characterization of novel thin-film and multilayer
structures in the Fe-Mn-Pd,[Co/Pt]n/FeMn and [Co/Pt]n/IrMn
system, with the goal of understanding the microscopic
origins of both in-plane and perpendicular exchange
anisotropy as manifested in systems exhibiting exchange
bias (ferromagnetic-antiferromagnetic heterostructures)
and exchange-spring (ferromagnetic soft-hard multilayers)
behavior. This work focuses on the properties of single
crystal heterostructures, containing various combinations
of these materials grown in our laboratory as epitaxial
thin films on lattice-matched substrates by ion-beam
deposition. Investigations will include the fabrication
of novel and unexplored spin-coupling geometries leading
to exchange bias, evaluation of critical dimensions
and length-scales associated with exchange-spring
behavior in two-phase nanostructures, measurement
of magnetic/transport properties, and advanced characterization
at relevant length scales, with special emphasis on
interfaces, using electron (NCEM/LBNL), photon (ALS/LBNL)
and neutron (IPNS/ANL) probes at DoE run national
user facilities. The fundamental goal is no less than
a microscopic understanding of exchange bias and exchange-spring
behavior at the atomic scale. The technological goal
is to develop appropriate predictive tools to microstructurally
tailor exchange-bias properties of AFM-FM structures
and to advance the practical science of exchange-spring
permanent magnets used in a variety of energy-related
applications.
Recent publications:
P. Blomqvist, Er. Girt, and Kannan
M. Krishnan,
"Magnetization processes in exchange-biased MnPd/Fe
bilayers," J. Appl. Phys. 95 (12): 8487-8489
(2004)
P. Blomqvist, David McCready, and
Kannan M. Krishnan,
"Growth of exchange-biased MnPd bilayers,"
J. Appl. Phys. 95 (12): 8019-8022 (2004)
P. Blomqvist, S. Srinath, S.G.E.
te Velthuis, and Kannan M. Krishnan, "Magnetization
processes in exchange-biased MnPd/Fe bilayers studied
by spin-polarized neutron reflectometry," J.
Appl. Phys. (submitted)
Recent oral presentations:
Xiaosong Ji "Growth and structure-property
correlations in perpendicular exchange biased magnetic
multilayers" 2005 APS March Meeting, March 21-25,
2005; Los Angeles, CA
Xiaosong Ji "Competing magnetic interactions
in perpendicular exchange-biased [Co/Pt]/FeMn multilayers"
50th Conference on Magnetism and Magnetic Materials,
Oct. 30th to Nov 3rd, San Jose, CA
Xiaosong Ji "Growth
and structure-property correlations in perpendicular
exchange biased (Co/Pt)n/FeMn multilayers",
APS March Meeting, Los Angeles, California, March
2005
Peter Blomqvist, "Magnetization
processes in exchange-
biased MnPd/Fe bilayers" MMM/Intermag Conference
in Anaheim, Los Angeles, January 2004
Kannan M. Krishnan, General Electric
John F. Welch Technology Center, Bangalore, India,
"Thin films and nanostructures", August
29, 2003
Exchange Bias
in AFM - FM Bilayers (in PDF format)
University of Glasgow, Department of Physics Colloquium
Recent poster presentations:
Exchange
coupling in nanoscale MnPd/Fe heterostructures
(in PowerPoint format), Peter Blomqvist and Kannan
M. Krishnan, ICM in Rome, 2003
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