Unusual criticality of Cu2Te2O5Br2 under pressure

Abstract We present measurements of the magnetic susceptibility χ ( T ) on Cu 2 Te 2 O 5 Br 2 under externally applied pressure. From our data we extract the pressure response of the antiferromagnetic phase transition at T 0 = 11.6 K 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 ∼ 8 kbar . In contrast, the phase transition temperature T 0 is significantly suppressed and not observable anymore at a pressure of 8.2 kbar.