Unusual criticality of Cu2Te2O5Br2Cu2Te2O5Br2 under pressure

We present measurements of the magnetic susceptibility χ(T)χ(T) on Cu2Te2O5Br2Cu2Te2O5Br2 under externally applied pressure. From our data we extract the pressure response of the antiferromagnetic phase transition at T0=11.6K and of the overall magnetic coupling strength. Our experiments indicate that with pressure the overall magnetic coupling strength increases by about 25% with applied pressure of only ∼8kbar. In contrast, the phase transition temperature T0T0 is significantly suppressed and not observable anymore at a pressure of 8.2 kbar.