Browsing by Author "Goodwin, AL"

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    Emergent frustration in co-doped β-Mn
    (American Physical Society, 2013-06-28) Paddison, JAM; Stewart, JR; Manuel, P; Courtois, P; McIntyre, GJ; Rainford, BD; Goodwin, AL
    We investigate low-temperature spin correlations in the metallic frustrated magnet beta-Mn1-xCox. Single-crystal polarized-neutron scattering experiments reveal the persistence of highly structured magnetic diffuse scattering and the absence of periodic magnetic order to T = 0.05 K. We employ reverse Monte Carlo refinements and mean-field theory calculations to construct an effective Hamiltonian which accounts for the magnetic scattering. The interactions we identify describe an emergent spin structure which mimics the triangular lattice antiferromagnet, one of the canonical models of frustrated magnetism. © 2013, American Physical Society.
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    Hydration as a trigger for new properties in inorganic materials
    (Australian Institute of Nuclear Science and Engineering, 2016-11-29) Duyker, SG; Peterson, VK; Kearley, GJ; Studer, AJ; Kepert, CJ; Hill, JA; Howard, CJ; Goodwin, AL
    The humble water molecule binds to metal ions strongly enough that it can have a significant distortive influence on the coordination geometry, yet weakly enough that it can be readily removed, thus providing scope for reversible chemical switching between structural forms. When this principle is applied in 3D coordination frameworks, the unique topological constraints of the framework can lead to new behaviours. Examples from our work will be presented, including anomalous mechanical properties enabled by unsaturated coordination spheres,[1] and new kinds of symmetry breaking transformations triggered by (de)hydration[2] (see figure).
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    β-Mn: emergent simplicity in a complex structure
    (Cornell University, 2013-02-04) Paddison, JAM; Stewart, JR; Manuel, P; Courtois, P; McIntyre, GJ; Rainford, BD; Goodwin, AL
    We investigate low-temperature spin correlations in the metallic frustrated magnet β-MnCo. Single-crystal polarised-neutron scattering experiments reveal the persistence of highly-structured magnetic diffuse scattering and the absence of periodic magnetic order to T = 0.05 K. We employ reverse Monte Carlo refinements and mean-field theory simulations to construct a simple effective Hamiltonian which accounts for the magnetic scattering. The interactions we identify describe an emergent spin structure which mimics the triangular lattice antiferromagnet. The observation of a simple collective magnetic state in a complicated crystal structure is surprising because it reverses the established paradigm of elaborate emergent states arising from many-body interactions on simple lattices. We suggest that structural complexity may provide a route to realising new states of correlated quantum matter.