  The effect of externally applied pressure on the magnetic behavior of
Cu2Te2O5(BrxCl{1-x})2 with x = 0, 0.73 and 1, is investigated by a combination
of magnetic susceptibility, neutron diffraction and neutron inelastic
scattering measurements. The magnetic transition temperatures of the x = 0 and
0.73 compositions are observed to increase linearly with increasing pressure at
a rate of 0.23(2) K/kbar and 0.04(1) K/kbar respectively. However, the bromide
shows contrasting behavior with a large suppression of the transition
temperature under pressure, at a rate of -0.95(9) K/kbar. In neutron inelastic
scattering measurements of Cu2Te2O5Br2 under pressure only a small change to
the ambient pressure magnetic excitations were observed. A peak in the density
of states was seen to shift from ~5 meV in ambient pressure to ~6 meV under an
applied pressure of 11.3 kbar, which was associated with an increase in the
overall magnetic coupling strength.
