Abstract
Spin-wave resonance has been observed at 9 GHz in thin films of Ni-Co alloys containing between 0 and 40% Co at temperatures between 4.2K and room temperature. The dispersion relationship, critical angle, linewidth and annealing results suggest that the surface spins are pinned by a surface layer about 100 AA thick. The exchange stiffness constant is found to have a value about a quarter of that obtained by other methods, namely approximately 100 meV A2.