Neutron-diffraction study of quadrupole order in TmTe: observation of a field-induced magnetic superstructure

The antiferroquadrupolar phase of TmTe has been characterized by neutron-di ffraction. In an applied magnetic held, the underlying ordered structure of the Tm quadrupole moments is disclosed by the appearance of antiferromagne tic superstructure peaks. The magnitude and direction of this induced magne tic component have been determined for different held directions. The resul ts are consistent with the order parameter O-2(2). (C) 1999 Elsevier Scienc e B.V. All rights reserved.