EVIDENCE FOR STATIONARY NONLINEAR EXCITATIONS IN SPECIFIC-HEAT OF DIPOLAR MAGNET KER(MOO4)(2)

Specific heat studies of a single crystal of a quasi-one-dimensional d ipolar magnet KEr(MoO4)(2) were performed in the temperature range fro m 2 to 6 K in magnetic fields up to 1 T. The fields were applied along the Er3+ chains. The behaviour of the magnetic specific heat was anal ysed in the frame of two limiting models: the sine-Gordon theory and t he Ising model in a magnetic field. The analysis revealed that the stu died system resembles Ising behaviour rather than the behaviour predic ted by sine-Gordon model. These results might be a preliminary indicat ion of the presence of stationary non-linear magnetic excitations in t he studied system. (C) 1998 Elsevier Science B.V. All rights reserved.