EXTERNAL QUADRUPOLE MAGNETIC-FIELD OF ANTIFERROMAGNETIC CR2O3

We report the results of an experimental study of the external magneti c field of an antiferromagnetic Cr2O3 single-crystal. They confirm rel iably that this field corresponds to a magnetic quadrupole field, as p redicted by Dzyaloshinskii [Solid State Comm. 82, 570 (1992)] and obse rved by D. N. Astrov and N. B. Ermakov [JETP Lett. 59, 297 (1994)]. Th e quadrupole moment of the sample was found to be several times smalle r than the value predicted by calculations. (C) 1996 American Institut e of Physics.