Magneto-optical properties of RMn6Sn6 (R = Gd, Tb, Dy, Ho, Er, Tm, Lu) single crystals

Single crystals of compounds in the series RMn6Sn6 (R = Gd-Tm, Lu) have bee n prepared by the flux growth technique. The crystal structure was found to be isotypic with HfFe6Ge6 for all of the compounds, and the variation of t he lattice parameters with the lanthanide element exhibit the lanthanide co ntraction. The polar Kerr effect has been measured between 1.3 and 5 eV, an d the structure of the spectra are similar for all of the compounds of the series. The maximum Kerr rotation found was 0.225 degrees in TbMn6Sn6, and the magnitude of the Kerr rotations scaled across the series as a function of the fraction saturation. This, combined with the temperature dependence, indicates that the Kerr rotation is primarily a function of the Mn moment and is independent of the lanthanide element present in the compound. The m ain features in the spectra shift to slightly higher energies as one moves from Gd to the end of the lanthanide series (i.e. Tm and Lu) which is relat ed to the contraction in the lattice parameters. (C) 1999 Elsevier Science B.V. All rights reserved.