1201.6143 (D. Hüvonen et al.)

Field-induced criticality in a gapped quantum magnet with bond disorder    [PDF]

D. Hüvonen, S. Zhao, M. Månsson, T. Yankova, E. Ressouche, C. Niedermayer, M. Laver, S. N. Gvasaliya, A. Zheludev

Neutron diffraction and calorimetric measurements are used to study the
field-induced quantum phase transition in
piperazinium-Cu$_2$(Cl$_{1-x}$Br$_x$)$_6$ ($x=0$, x=3.5% and x=7.5%), a
prototypical quantum antiferromagnet with random bonds. The critical indexes
$\phi$ and $\beta$ are determined. The findings contradict some original
predictions for Bose Glass based on the assumption $z=d$, but are consistent
with recent theoretical results implying $zreveal that disorder has a profound effect on the lowest-energy magnetic gap
excitation in the system.

View original: http://arxiv.org/abs/1201.6143