High magnetic field behaviour of the triangular lattice antiferromagnet, CuFeO2

The magnetic phase diagram of the triangular lattice antiferromagnet CuFeO2 has been studied using single-crystal neutron diffraction measurements in a magnetic field of up to 14.5 T and also by magnetisation measurements up to 12 T. At low temperature, two well-defined first-order magnetic phase transitions were found in this range of applied magnetic field: at H-C1 = 7.6 T and H-C2 = 13.2 T, with the later one corresponding to a transition from a four to five sublattice structure. Cooling the sample in a high magnetic field resulted in the locking of the magnetic structure into the intermediate temperature incommensurate structure. (C) 2001 Elsevier Science B.V. All rights reserved.