Imaging spiral magnetic domains in Ho metal using circularly polarized Bragg diffraction

We have used circularly polarized x rays to image the spiral magnetic domain structure in a single crystal of Ho metal. In these structures, the magnetization direction rotates between successive atomic layers forming a helix. At magnetic Bragg diffraction peaks, circularly polarized x rays are sensitive to the handedness of such a helix (i.e., either right or left handed). By reversing the helicity of the incident beam with phase-retarding optics and measuring the difference in the Bragg scattering, contrast between domains of opposing handedness can be obtained. (C) 2004 American Institute of Physics.