Neutron Scattering Study of Spin Dynamics at the Magnetic Phase Transition in Two-Dimensional Planar Ferromagnet K₂CuF₄

Abstract

Spin dynamics of K 2 CuF 4 has been studied by neutron scattering technique. The motivation of our study is to make an extention of the previous study by Moussa and Villain, because of the increasing interest in the nature of the transition which might be close to the Kosterlitz-Thouless (KT) type. The wave number dependent magnon frequency and width are systematically measured as a function of temperature and noticiable evolution of wave number dependent dynamics has been observed. In a low wave number region, a steap decrease in magnon frequency was observed at the transition supporting the above conjecture.