New germanates RCrGeO5 (R=Nd-Er, Y): Synthesis, structure, and properties

Roman V. Shpanchenko, Alexander A. Tsirlin, Ekaterina S. Kondakova, Evgeny V. Antipov, Catherine Bougerol, Joke Hadermann, Gustaaf van Tendeloo, Hiroya Sakurai, Eiji Takayama-Muromachi

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

The new complex germanates RCrGeO5 (R=Nd-Er, Y) have been synthesized and investigated by means of X-ray powder diffraction, electron microscopy, magnetic susceptibility and specific heat measurements. All the compounds are isostructural and crystallize in the orthorhombic symmetry, space group Pbam, and Z=4. The crystal structure of RCrGeO5, as refined using X-ray powder diffraction data, includes infinite chains built by edge-sharing Cr+3O6 octahedra with two alternating Cr-Cr distances. The chains are combined into a three-dimensional framework by Ge2O8 groups consisting of two edge-linked square pyramids oriented in opposite directions. The resulting framework contains pentagonal channels where rare-earth elements are located. Thus, RCrGeO5 germanates present new examples of RMn2O5-type compounds and show ordering of Cr+3 and Ge+4 cations. Electron diffraction as well as high-resolution electron microscopy confirm the structure solution. Magnetic susceptibility data for R=Nd, Sm, and Eu are qualitatively consistent with the presence of isolated 3d (antiferromagnetically coupled Cr+3 cations) and 4f (R+3) spin subsystems in the RCrGeO5 compounds. NdCrGeO5 undergoes long-range magnetic ordering at 2.6 K, while SmCrGeO5 and EuCrGeO5 do not show any phase transitions down to 2 K.

Original languageEnglish
Pages (from-to)2433-2441
Number of pages9
JournalJournal of Solid State Chemistry
Volume181
Issue number9
DOIs
Publication statusPublished - Sep 2008
Externally publishedYes

Keywords

  • Chromium germanium oxide
  • Crystal structure
  • Magnetic properties

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