Field-Induced Magnetic Phase Transitions and Correlated Electronic States in the Hexagonal RAgGe and RPtIn Series

摘要

The present work was initially motivated by the desire to continue the study of complex metamagnetism in relation to the crystal structure of various compounds; this study already included tetragonal compounds like HoNi(sub 2)C (Canifield 1997b; Kalatsky l998) and DyAgDb(sub 2) (Myers 1999), in which the rare earths occupy unique tetragonal positions. We intended to find hexagonal systems suited for such a study, with complex metamagnetic properties, and the search for extremely anisotropic hexagonal compounds turned into a rewarding exploration. We identified and grew most of the heavy rare earth members of two isostructural series, RAgGe and RPtin, both belonging to the hexagonal Fe(sub 2)P family of materials. In each of these series we found one compound, TmAgGe, and TbPtln respectively, that was suitable for a simple study of angular dependent metamagnetism: they had three rare earth ions in the unit cell, positioned at a unique crstallographic site with orthorhombic point symmetry.The magnetization of both TmAgGe and TbPtln was extremely anisotropic, with larger values for the in-plane orientation of the applied field than in the axial direction.