  The field induced quantum phase transitions in the disorder-free and
disordered samples of the spin ladder material (CH_3)_2CHNH_3Cu(Cl_{1-x}Br_x)_3
are studied using magnetic calorimetry and magnetic neutron diffraction on
single crystal samples. Drastically different critical indexes and correlation
lengths in the high field phase are found for two different orientations of the
applied field. It is argued that for a field applied along the crystallographic
c axis, as in previous studies [1], the transition is best described as an
Ising transition in random field and anisotropy, rather than as a magnetic Bose
Glass to Bose Condensate transition.
  [1] Tao Hong, A. Zheludev, H. Manaka, and L.- P. Regnault, Phys. Rev. B 81,
060410 (2010).
