%0 Journal Article
%A Stock, C.
%A Rodriguez, E. E.
%A Lee, N.
%A Green, M. A.
%A Demmel, F.
%A Ewings, R. A.
%A Fouquet, P.
%A Laver, M.
%A Niedermayer, Ch.
%A Su, Y.
%A Nemkovskiy, Kirill
%A Rodriguez-Rivera, J. A.
%A Cheong, S.-W.
%T Solitary Magnons in the S = 5/2 Antiferromagnet CaFe$_2$O$_4$
%J Physical review letters
%V 117
%N 1
%@ 1079-7114
%C College Park, Md.
%I APS
%M FZJ-2016-07345
%P 017201
%D 2016
%X CaFe2O4 is a S=52 anisotropic antiferromagnet based upon zig-zag chains having two competing magnetic structures, denoted as the A (↑↑↓↓) and B (↑↓↑↓) phases, which differ by the c-axis stacking of ferromagnetic stripes. We apply neutron scattering to demonstrate that the competing A and B phase order parameters result in magnetic antiphase boundaries along c which freeze on the time scale of ∼1  ns 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 ∼1–2 c-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 A+B orders as well as localization of spin excitations in a classical magnet.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000378878700007
%$ pmid:27419585
%R 10.1103/PhysRevLett.117.017201
%U https://juser.fz-juelich.de/record/824843