Abstract
is a anisotropic antiferromagnet based upon zig-zag chains having two competing magnetic structures, denoted as the () and () phases, which differ by the -axis stacking of ferromagnetic stripes. We apply neutron scattering to demonstrate that the competing and phase order parameters result in magnetic antiphase boundaries along which freeze on the time scale of at the onset of magnetic order at 200 K. Using high resolution neutron spectroscopy, we find quantized spin wave levels and measure 9 such excitations localized in regions -axis lattice constants in size. We discuss these in the context of solitary magnons predicted to exist in anisotropic systems. The magnetic anisotropy affords both competing orders as well as localization of spin excitations in a classical magnet.
- Received 8 March 2016
DOI:https://doi.org/10.1103/PhysRevLett.117.017201
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