Magnetic properties and structural transitions of orthorhombic fluorite-related compounds Ln3MO7 (Ln = rare earths, M = transition metals)

• Wakeshima, Makoto

• Hinatsu, Yukio

Abstract

Magnetic properties and structural transitions of ternary rare-earth transition-metal oxides Ln3MO7 (Ln=rare earths, M=transition metals) were investigated. In this study, we prepared a series of molybdates Ln3MoO7 (Ln=La～Gd). They crystallize in an orthorhombic superstructure of cubic fluorite with space group P2_[1]2_[1]2_[1], in which Ln^[3+] ions occupy two different crystallographic sites (the 8-coordinated and 7-coordinated sites). All of these compounds show a phase transition from the space group P2_[1]2_[1]2_[1] to Pnma in the temperature range between 370 and 710 K. Their magnetic properties were characterized by magnetic susceptibility measurements from 1.8 to 400 K and specific heat measurements from 0.4 K to 400 K. Gd3MoO7 shows an antiferromagnetic transition at 1.9 K. Measurements of the specific heat for Sm3MoO7 and the analysis of the magnetic specific heat indicate a "two-step" antiferromagnetic transition due to the ordering of Sm magnetic moments in different crystallographic sites, i.e., with decreasing temperature, the antiferromagnetic ordering of the 7-coordinated Sm ions occur at 2.5 K, and then the 8-coordinated Sm ions order at 0.8 K. The results of Ln3MoO7 were compared with the magnetic properties and structural transitions of Ln3MO7 (M=Nb, Ru, Sb, Ta, Re, Os, or Ir).

Journal

• Journal of Solid State Chemistry

  Journal of Solid State Chemistry 183 (11), 2681-2688, 2010-11

  Elsevier

Keywords

• Magnetic properties
• Structural transition
• Rare earth
• Magnetic susceptibility
• Specific heat
• Molybdenum
• Defect-fluorite structure

Details

• CRID: 1050282813983792512
• NII Article ID: 120002662657
• HANDLE: 2115/44436
• ISSN: 00224596
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles