INCOMMENSURATE MODULATIONS IN THE MAGNETIC-STRUCTURE OF THE MAGNETIC SUPERCONDUCTOR HONI2B2C A HIGH-RESOLUTION NEUTRON POWDER DIFFRACTION STUDY

Neutron diffraction techniques have been used to study the magnetic st ructure of powder samples of the superconducting HoNi2B2C. In addition to the modulation of the moments along c reported previously, we obs erve in the vicinity of 5 K, where the compound exhibits reentrant beh avior, a modulation of the moments along a. We demonstrate that all p resently available experimental data on single crystals as well as pow der samples contain unambiguous evidence for a modulation of the momen ts along a with a wave vector, q(a), of approximately 0.585a*. We con clude that this modulation of the moments along a is characteristic o f the magnetic structure of HoNi2B2C.