The newly commissioned Let spectrometer on the ISIS Second
Target Station, combined with the vertical-opening 9 T magnet and
dilution refrigerator insert, offers unparalleled opportunities for
probing atomic dynamics with high resolution and wide coverage in all
three momentum directions.
We have used Let to explore the magnetic behaviour in
CoNb2O6. We recently showed this material to be the first experimental
realization of the much theoretically-studied Ising chain in transverse
field. Here ‘quantum melting’ of order occurs above magnetic fields of
5.5 T, in which spontaneous long-range order is replaced by a gapped
‘quantum paramagnet.’ We have probed the magnetic behaviour in this
high-field phase at 7 T along both interchain crystal directions and
confirmed a model of frustrated interchain couplings. Knowing the
strengths of these couplings is important as they are responsible for
the formation of a ‘Zeeman’ ladder of confined bound states in zero
field.
IM Cabrera, R Coldea (Oxford University), R Bewley, J Taylor (ISIS), D Prabhakaran (Oxford Univesity)
Research date: August 2011
Further Information
Contact: Dr R Coldea, r.coldea@physics.ox.ac.uk
Further reading: R Coldea et al., Science 327 (2010) 177
