Magnetic phase diagram of CuB2O4

Abstract

The magnetic structure of CuB2O4 is investigated by optical second harmonic generation. A rich second harmonic spectrum is observed and at least three different magnetic phases in the magnetic-field/temperature plane are revealed for magnetic fields applied along the principal axes of the compound. In the temperature ranges T<TR and TR<T<TN (with TR=10 K and TN=21 K) antiferromagnetic phases without and with a weak spontaneous ferromagnetic component are observed, respectively. A static magnetic field supports the phase directly below TN and finally suppresses the magnetic reorientation at TR.