Neutron-scattering experiments on the two-dimensional easy-plane antiferromagnet K2FeF4

Abstract

Spin-wave dispersion and sublattice magnetization of K2FeF4 have been examined by neutron scattering and analyzed in terms of renormalized spin-wave theory appropriate for the easy-plane square lattice. Numerical results are J = (−11.5 ± 0.6) cm−1, D = (3.6 ± 0.5) cm−1, and E(T = 0) = (−0.37 ± 0.10) cm−1. Near TN the sublattice magnetization follows a power law, with TN = (62.7 ± 0.6) K and β = 0.13 ± 0.01.