HELICAL MAGNETIC ORDER AND SPIN SLIPS IN HOLMIUM-YTTRIUM SUPERLATTICES

The chemical and magnetic structures of a series of Ho/Y superlattices have been studied using X-ray and neutron scattering techniques. The X-ray diffraction results show that the superlattices have a high degr ee of crystalline order, with sharp interfaces between the two materia ls. From the neutron scattering the Ho3+ magnetic moments are found to form a basal-plane helic at all temperatures in the ordered phase, wi th an apparent suppression of the low-temperature cone base. The chira lity of the helix is coherently maintained across the yttrium with an effective, temperature-independent turn angle of 51.1(1.5)-degrees. Be low almost-equal-to 30 K the Ho3+ moments form commensurate spin-slip structures.