Frozen spin-wave structure on the NiO(100) surface observed by metastable He23Sscattering

Elastic scattering of metastable $2^3$S He has been used for the first time to determine the long-range spin ordering on the surface of an antiferromagnetic insulator. The diffraction pattern obtained from a NiO(100) surface is interpreted as a frozen spin-wave structure in the 〈10〉 direction with a period of 6×a. The diffraction arises from a spatial variation of the beam attenuation due to scattering from the periodic local spin ordering on the surface and is not caused by a spin-spin interaction. The results have been modeled with a modified version of the eikonal approximation using a dissipative, hard, corrugated wall.