Characterisation of spin-waves in copper(II) deuteroformate tetradeuterate: a square S=1/2 Heisenberg antiferromagnet

Copper(II) formate tetrahydrate (CFTH) is a model square S = 1/2 Heisenberg antiferromagnet with T-N = 16.54 +/- 0.05 K. The dispersion of spin-waves in the magnetic layers of a fully deuterated sample of this material has been mapped at 4.3 K by inelastic neutron scattering from the zone centre at 0.38 meV to the zone boundary at 14.8 meV, The data are described well by spin-wave theory with a small correction for quantum fluctuations, yielding a nearest-neighbour in-plane exchange constant of 6.3 +/- 0.2 meV, (C) 1999 Elsevier Science Ltd, All rights reserved