Polyborides with Th2NiB10-Type Structure: Synthesis, Crystal Structure, and Magnetic and Electrical Properties
| Autor: | Arne Lang, Thomas Konrad, Klaus Hartjes, Rolf-Dieter Hoffmann, Wolfgang Jeitschko |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Magnetic moment
Chemistry Yttrium borides Condensed Matter Physics Magnetic susceptibility Electronic Optical and Magnetic Materials Inorganic Chemistry Magnetization Paramagnetism chemistry.chemical_compound Crystallography Materials Chemistry Ceramics and Composites Antiferromagnetism Orthorhombic crystal system Physical and Theoretical Chemistry Metamagnetism Nuclear chemistry |
| Zdroj: | Journal of Solid State Chemistry. 154:246-253 |
| ISSN: | 0022-4596 |
| DOI: | 10.1006/jssc.2000.8844 |
| Popis: | The new rare-earth nickel polyborides R 2 NiB 10 ( R =Y, Ce–Nd, Sm, Gd–Ho) were prepared by reacting cold-pressed pellets of the elemental components in an arc-melting furnace, followed by annealing in evacuated silica tubes. They crystallize with the orthorhombic Th 2 NiB 10 -type structure, which was refined from X-ray powder diffractometer data of Ce 2 NiB 10 ( a =565.4(1) pm, b =1125.8(2) pm, c =419.6(1) pm) and Nd 2 NiB 10 ( a =561.4(1) pm, b =1119.2(2) pm, c =417.7(1) pm). The magnetic properties of these polyborides and also of Th 2 CoB 10 and Th 2 NiB 10 were determined with a superconducting quantum interference magnetometer between 2 and 400 K with magnetic flux densities up to 5.5 T. Y 2 NiB 10 , Th 2 CoB 10 , and Th 2 NiB 10 are Pauli paramagnetic. The others show Curie–Weiss behavior with magnetic moments corresponding to those of the free R 3+ ions, with the exception of Ce 2 NiB 10 , where cerium has a mixed valence and Sm 2 NiB 10 with the van Vleck paramagnetic Sm 3+ ion. Antiferromagnetic order was observed for the compounds R 2 NiB 10 ( R =Pr, Nd, Sm, Gd–Ho) with Neel temperatures ranging between 8 K for Pr 2 NiB 10 and 33 K for Gd 2 NiB 10 . Tb 2 NiB 10 , Dy 2 NiB 10 , and Ho 2 NiB 10 are metamagnetic. Electrical resistivity measurements reflect the magnetic ordering temperatures and indicate metallic behavior for all compounds. |
| Databáze: | OpenAIRE |
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