Highly-symmetrized MnAu nanoalloys may possess high magnetic moments for potential application. The magnetic properties of MnAu nanoclusters exhibit strong dependence on the cluster sizes and morphologies. Determining the most stable morphologies as well

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Theoretical and Experimental Characterization of
Structures of MnAu Nanoclusters
Xiao Cheng Zeng, Jeffrey E. Shield, and David J.
Sellmyer (Nebraska MRSEC) He Kai (University of
Maryland)
Highly-symmetrized MnAu nanoalloys may possess
high magnetic moments for potential application.
The magnetic properties of MnAu nanoclusters
exhibit strong dependence on the cluster sizes
and morphologies. Determining the most stable
morphologies as well as their spin-polarization
patterns is important for their further
application. Researchers at University of
Nebraska MRSEC performed a joint
theoretical/experimental study to
investigate relative stabilities of various
highly-symmetrized morphologies of MnAu clusters
with different sizes (ACS NANO 5, 9966 9 (2011)).
Based on an extensive search, they found that the
antiferromagnetic spin configurations are the
most stable for all the morphologies
investigated. As the size increases, the most
stable morphology of MnAu nanocluster evolves
from a core-shell structure to L10 structure, and
starting from 1.7 nm size the L10 structures
become more stable, confirmed by the
high-resolution transmission electron microscopy
experiment. Both the antiferromagnetic and
ferromagnetic states for the L10 MnAu
nanoclusters larger than 2 nm are likely to be
energetically stable at room temperature. Because
their closeness in cohesive energies, there is
possible existence of both antiferromagnetic and
ferromagnetic states for L10 MnAu nanoclusters in
different sizes, and this mixed system can be
useful for applications such as exchange bias.
These programs are supported by the National
Science Foundation, Division of Materials
Research, Materials Research Science and
Engineering Program, Grant 0820521.