2024-03-29T07:16:13Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/444362022-11-17T02:08:08Zhdl_2115_20039hdl_2115_116Magnetic properties and structural transitions of orthorhombic fluorite-related compounds Ln3MO7 (Ln = rare earths, M = transition metals)Wakeshima, MakotoHinatsu, Yukioopen accessMagnetic propertiesStructural transitionRare earthMagnetic susceptibilitySpecific heatMolybdenumDefect-fluorite structure431Magnetic 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).Elsevier2010-11engjournal articleAMhttp://hdl.handle.net/2115/44436https://doi.org/10.1016/j.jssc.2010.09.0050022-4596Journal of Solid State Chemistry1831126812688https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/44436/1/JSSC183-11_2681-2688.pdfapplication/pdf869.92 KB2010-11