An Investigation of the Magnetic Structure and Excitations in K2CoxFe1-xF4

Neutron scattering techniques have been used to investigate the magnetic structure of K2CoxF1-xF4 with x=0.2 and x=0.6. The x=0.6 sample exhibits only one magnetic phase transition, at TN=92.2+or-0.1K. The x=0.2 sample has two magnetic phase transitions; below TN=66+or-1K the axial spin components order, while below a well defined transition at TL=32+or-2K the transverse components also order. The spin wave dispersion relations have been measured for both samples using inelastic neutron scattering techniques.