TY  - JOUR
AU  - Stock, C.
AU  - Rodriguez, E. E.
AU  - Lee, N.
AU  - Green, M. A.
AU  - Demmel, F.
AU  - Ewings, R. A.
AU  - Fouquet, P.
AU  - Laver, M.
AU  - Niedermayer, Ch.
AU  - Su, Y.
AU  - Nemkovskiy, Kirill
AU  - Rodriguez-Rivera, J. A.
AU  - Cheong, S.-W.
TI  - Solitary Magnons in the S = 5/2 Antiferromagnet CaFe$_2$O$_4$
JO  - Physical review letters
VL  - 117
IS  - 1
SN  - 1079-7114
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2016-07345
SP  - 017201
PY  - 2016
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000378878700007
C6  - pmid:27419585
DO  - DOI:10.1103/PhysRevLett.117.017201
UR  - https://juser.fz-juelich.de/record/824843
ER  -