SPIN REORIENTATION IN THE EASY-PLANE HEXAGONAL ANTIFERROMAGNET UNDER A CANTED MAGNETIC-FIELD

Spin reorientation process in the quasi-one-dimensional easy-plane antiferromagnet on a stacked triangular lattice has been considered theoretically and studied in an experiment on CsMnBr3. The second-order phase transition associated with the flip of two pairs of sublattices has been shown to persist if the magnetic field is canted at an angle-phi from the basal plane. The field and angular dependences of the magnetic torques measured at T = 1.8 K, although in qualitative agreement with the classical theory. demonstrate a strong effect of quantum fluctuations.