Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)
MA 18.28: Poster
Dienstag, 26. Februar 2008, 15:15–18:30, Poster E
Magnetic properties of rare earth transition metal borides R2−xNi21B6 (R = Sc, Zr, Lu) and Lu1.65−xRxNi21−yMyB6 (R = Y, Zr; M = Cu) — •Roman Gumeniuk, Walter Schnelle, Helge Rosner, Yuri Prots, Igor Veremchuk, Andreas Leithe-Jasper, and Yuri Grin — Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany
The crystal structures of the compounds R2−xNi21B6 (R = Sc, Zr, Lu) have been determined by means of single crystal refinement and belong to the Cr23C6 type. The temperature dependence of the magnetic susceptibility of these compounds is described by a modified Curie-Weiss law. The unexpectedly large paramagnetic moment (µeff = 1.49 µB/f.u.) for Lu1.65Ni21B6 could indicate that the compound is close to ferromagnetic ordering. LSDA band structure calculations suggest a ferromagnetic ground state where only the Ni atoms at the crystallographic 4a position exhibit a sizable magnetic moment. Experimentally no magnetic order was observed down to 1.8 K. Substitution of Lu by Y or Zr, or Ni by Cu in the crystal structure leads to the suppression of the tendency towards ferromagnetism.