Magnetic phase diagram of the strongly frustrated quantum spin chain system PbCuSO4(OH)2 in tilted magnetic fields

We report the H-T phase diagram of S = 1/2 strongly frustrated anisotropic spin chain material linarite PbCuSO4(OH)(2) in tilted magnetic fields up to 10 T and temperatures down to 0.2 K. By means of torque magnetometry we investigate the phase diagram evolution as the magnetic field undergoes rotation in ba * and bc planes. The key finding is the robustness of the high field spin density wavelike phase, which may persist even as the external field goes orthogonal to the chain direction b. In contrast, the intermediate collinear antiferromagnetic phase collapses at moderate deflection angles with respect to b axis.