Pressure effect on the Néel temperature in La2CuO4

The effects of hydrostatic pressure up to 1.3 GPa on the Neel temperature in orthorhombic antiferromagnetic La 2 CuO 4+δ have been investigated using the 139 La NQR method. A positive sign of the pressure derivative, d T N /d P = 7.1 K/GPa, as well as an increase in the critical index β from 0.29 at ambient pressure to 0.33 at 1.3 GPa have been observed. The results were processed using the Green function method.