Semimetallic paramagnetic nano-Bi2Ir and superconducting ferromagnetic nano-Bi3Ni by microwave-assisted synthesis and room temperature pseudomorphosis

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Uniform nanocrystals of the intermetallic compounds Bi2Ir (diameter ' 50 nm) and Bi3Ni (typical size 200×600 nm) were obtained by a microwave-assisted polyol process at 240 °C. The method was also applied to the spatially confined reaction environment in the microporous exo-template SBA-15 resulting in Bi3Ni particles of about 6 nm. Non-crystalline bundles of parallel Bi3Ni nanofibres that have an individual diameter of less than 1 nm were obtained by reductive pseudomorphosis of the subiodide Bi12Ni4I3 at room temperature. Magnetic susceptibility measurements demonstrate coexistence of ferromagnetism and superconductivity in a single phase for the nanostructured Bi3Ni materials. Curie temperature, coercive field, remnant magnetization, saturation moment, diamagnetic screening, and critical field vary with particle size. The crystal structure of Bi2Ir was determined by Rietveld refinement of powder X-ray diffraction data. Bi2Ir crystallizes in the monoclinic arsenopyrite type (space group P21/c), a superstructure of the markasite type, with a = 690.11(1), b = 678.85(1), c = 696.17(1) pm, and β = 116.454(1)°. In contrast to most of the other phases of this type, the Bi2Ir is not a diamagnetic semiconductor but a weakly paramagnetic semimetal. Conductivity measurements down to 4 K and magnetization measurements in a field of μ0H = 10mT down to 1.8 K give no evidence for a transition into the superconducting state. Bonding analysis shows prevailing contribution of Bi-Bi interactions to the conduction, whereas Bi-Ir bonding is mostly covalent and localized.


Original languageEnglish
Pages (from-to)2035-2043
Number of pages9
JournalZeitschrift fur Anorganische und Allgemeine Chemie
Issue number12-13
Publication statusPublished - Oct 2012

External IDs

ORCID /0000-0002-2391-6025/work/142250230


ASJC Scopus subject areas


  • Ferromagnetism, Microwave-assisted polyol process, Nanostructured intermetallics, Pseudomorphosis, Superconductivity

Library keywords