11B-NMR study of low-temperature phase transition in CuB2O4

The material CuB2O4 presents a variety of phases in the B–T phase diagram, caused by the frustration and the Dzialoshinskii–Moriya interaction. In order to investigate the nature of the phase transitions, a 11B-NMR experiment on CuB2O4 has been performed under an applied magnetic field along the a-axis down to 0.4 K. A new incommensurate–incommensurate phase transition has been found at 0.8 K under a field of 0.5 T. Further, another phase transition has been observed at 4.7 K under a field of about 2 T, which is consistent with the transition reported by the neutron diffraction experiment.