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Title: Magnetic interactions in praseodymium ruthenate Pr{sub 3}RuO{sub 7} with fluorite-related structure

Abstract

Solid solutions Pr{sub 3}(Ru{sub 1-x}Ta{sub x})O{sub 7} (0≤x≤1.0) and (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7} (0≤x≤0.7) were obtained as a single phase compound. They crystallize in an orthorhombic superstructure derived from that of the cubic fluorite with space group Cmcm. The results of the Rietveld analysis for X-ray diffraction profiles of Pr{sub 3}(Ru{sub 1-x}Ta{sub x})O{sub 7} showed that Ru and Ta atoms are randomly situated at the six-coordinate 4b site. For (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7}, with increasing the concentration of Y ions (x value), the smaller Y ions occupy selectively the seven-coordinate 8g site rather than the eight-coordinate 4a site. Through magnetic susceptibility measurements for Pr{sub 3}(Ru{sub 1-x}Ta{sub x})O{sub 7}, the antiferromagnetic transition temperatures decrease linearly with increasing x value, and at x=0.75 no magnetic ordering was found down to 1.8 K, indicating the magnetic interaction is not one-dimensional, but three-dimensional. On the other hand, the antiferromagnetic transition temperature for (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7} decreases with increasing x value, but above x≥0.50 it becomes constant (~12 K). This result indicates that Pr{sup 3+} ions at the seven-coordinate site greatly contribute to the antiferromagnetic interactions observed in (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7}. Density functional calculations of Pr{sub 3}RuO{sub 7} demonstratemore » that the electronic structure gives insulating character and that oxygen 2p orbitals hybridize strongly with Ru 4d orbitals in the valence band (VB). Near the top of VB, the Pr 4 f orbitals at the seven-coordinated site also show a weak hybridization with the O(1) 2p orbitals. The Ru-O(1)-Pr superexchange pathway take part in three-dimensional magnetic interaction and play an important role in an enhancement of long-range magnetic ordering. - Graphical abstract: The spin densities and the spin polarization of Pr{sub 3}RuO{sub 7} are shown. Significant spin polarization is seen on the magnetic Pr and Ru ions, but there is also some on the O(1), (3) ligands of Ru. - Highlights: • New fluorite-related quaternary praseodymium ruthenates were prepared. • Pr{sub 3}RuO{sub 7} shows an antiferromagnetic transition at 55 K. • The Ru-O-Pr superexchange interactions are three-dimensional.« less

Authors:
; ; ;
Publication Date:
OSTI Identifier:
22658293
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 250; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DENSITY FUNCTIONAL METHOD; ELECTRONIC STRUCTURE; EXPERIMENTAL DATA; FLUORINE COMPOUNDS; INTERACTIONS; MAGNETIZATION; ORTHORHOMBIC LATTICES; PRASEODYMIUM IONS; RUTHENIUM COMPOUNDS; RUTHENIUM IONS; SPACE GROUPS; SPIN ORIENTATION; X-RAY DIFFRACTION; YTTRIUM IONS

Citation Formats

Inabayashi, Masaki, Doi, Yoshihiro, Wakeshima, Makoto, and Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.jp. Magnetic interactions in praseodymium ruthenate Pr{sub 3}RuO{sub 7} with fluorite-related structure. United States: N. p., 2017. Web. doi:10.1016/J.JSSC.2017.03.025.
Inabayashi, Masaki, Doi, Yoshihiro, Wakeshima, Makoto, & Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.jp. Magnetic interactions in praseodymium ruthenate Pr{sub 3}RuO{sub 7} with fluorite-related structure. United States. doi:10.1016/J.JSSC.2017.03.025.
Inabayashi, Masaki, Doi, Yoshihiro, Wakeshima, Makoto, and Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.jp. 2017. "Magnetic interactions in praseodymium ruthenate Pr{sub 3}RuO{sub 7} with fluorite-related structure". United States. doi:10.1016/J.JSSC.2017.03.025.
@article{osti_22658293,
title = {Magnetic interactions in praseodymium ruthenate Pr{sub 3}RuO{sub 7} with fluorite-related structure},
author = {Inabayashi, Masaki and Doi, Yoshihiro and Wakeshima, Makoto and Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.jp},
abstractNote = {Solid solutions Pr{sub 3}(Ru{sub 1-x}Ta{sub x})O{sub 7} (0≤x≤1.0) and (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7} (0≤x≤0.7) were obtained as a single phase compound. They crystallize in an orthorhombic superstructure derived from that of the cubic fluorite with space group Cmcm. The results of the Rietveld analysis for X-ray diffraction profiles of Pr{sub 3}(Ru{sub 1-x}Ta{sub x})O{sub 7} showed that Ru and Ta atoms are randomly situated at the six-coordinate 4b site. For (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7}, with increasing the concentration of Y ions (x value), the smaller Y ions occupy selectively the seven-coordinate 8g site rather than the eight-coordinate 4a site. Through magnetic susceptibility measurements for Pr{sub 3}(Ru{sub 1-x}Ta{sub x})O{sub 7}, the antiferromagnetic transition temperatures decrease linearly with increasing x value, and at x=0.75 no magnetic ordering was found down to 1.8 K, indicating the magnetic interaction is not one-dimensional, but three-dimensional. On the other hand, the antiferromagnetic transition temperature for (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7} decreases with increasing x value, but above x≥0.50 it becomes constant (~12 K). This result indicates that Pr{sup 3+} ions at the seven-coordinate site greatly contribute to the antiferromagnetic interactions observed in (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7}. Density functional calculations of Pr{sub 3}RuO{sub 7} demonstrate that the electronic structure gives insulating character and that oxygen 2p orbitals hybridize strongly with Ru 4d orbitals in the valence band (VB). Near the top of VB, the Pr 4 f orbitals at the seven-coordinated site also show a weak hybridization with the O(1) 2p orbitals. The Ru-O(1)-Pr superexchange pathway take part in three-dimensional magnetic interaction and play an important role in an enhancement of long-range magnetic ordering. - Graphical abstract: The spin densities and the spin polarization of Pr{sub 3}RuO{sub 7} are shown. Significant spin polarization is seen on the magnetic Pr and Ru ions, but there is also some on the O(1), (3) ligands of Ru. - Highlights: • New fluorite-related quaternary praseodymium ruthenates were prepared. • Pr{sub 3}RuO{sub 7} shows an antiferromagnetic transition at 55 K. • The Ru-O-Pr superexchange interactions are three-dimensional.},
doi = {10.1016/J.JSSC.2017.03.025},
journal = {Journal of Solid State Chemistry},
number = ,
volume = 250,
place = {United States},
year = 2017,
month = 6
}
  • New fluorite-related quaternary rare earth oxides Pr{sub 2}YRuO{sub 7} and La{sub 2}TbRuO{sub 7} have been prepared. They crystallize in an orthorhombic superstructure of cubic fluorite with space group Cmcm. Through magnetic susceptibility and specific heat measurements, Pr{sub 2}YRuO{sub 7} shows an antiferromagnetic transition at 27 K, which is considerably lowered compared with that for Pr{sub 3}RuO{sub 7}. Analysis of the magnetic specific heat indicates that the magnetic behavior observed at 27 K for Pr{sub 2}YRuO{sub 7} is predominantly due to the magnetic interactions between Ru ions, and that the interactions between the Pr{sup 3+} and Ru{sup 5+} ions are alsomore » important. La{sub 2}TbRuO{sub 7} shows magnetic ordering at 9.0 K, which is ascribed to the magnetic ordering between Ru{sup 5+} ions from the analysis of the magnetic specific heat data. - Graphical abstract: New fluorite-related quaternary rare earth oxides Pr{sub 2}YRuO{sub 7} and La{sub 2}TbRuO{sub 7} have been prepared. Through magnetic susceptibility and specific heat measurements, Pr{sub 2}YRuO{sub 7} and La{sub 2}TbRuO{sub 7} show an antiferromagnetic transition at 27 and 9.0 K, respectively. Display Omitted - Highlights: • New fluorite-related quaternary rare earth oxides LnLn’{sub 2}RuO{sub 7} have been prepared. • Pr{sub 2}YRuO{sub 7} shows an antiferromagnetic transition at 27 K. • La{sub 2}TbRuO{sub 7} shows magnetic ordering at 9.0 K. • Their magnetic exchange mechanism has been elucidated by the magnetic entropy change.« less
  • Ionic conductivity data of yttria zirconia, Y/sub 4x/Zr/sub 1-4x/O/sub 2-2x/, reported in the literature as functions of oxygen vacancy concentration, x, and temperature, T, have been analyzed according to a theoretical model developed in a previous paper and applied to calcia stabilized zirconia. Because of the different charge compensation mechanism in yttria stabilized zirconia, Y/sub 4x/Zr/sub 1-4x/O/sub 2-2x/, than that in calcia stabilized zirconia, Ca/sub 2x/Zr/sub 1-2x/O/sub 2-2x/, the theory predicts the occurrence of a maximum of ionic conductivity at an oxygen vacancy concentration, x = 0.03125 (= 1/32), which is just half the oxygen vacancy concentration at the maximum,more » x = 0.0625 (= 1/16), in calcia stabilized zirconia. This was clearly confirmed by recent experimental results of Ioffe et al. and appears to substantiate further the basic validity of the theoretical model. Results of the theoretical analysis on yttria stabilized zirconia obtained herein are compared with those on calcia stabilized zirconia are also discussed in relation to the ionic conductivity data of the various rare earth oxide-stabilized zirconia systems. The basic assumptions and limitations of the theoretical model are critically examined, and possible modifications of the theoretical model are suggested.« less
  • Crystal structures and magnetic properties of the ternary oxides Ln{sub 3}NbO{sub 7} (Ln=La, Pr, Nd, Sm-Lu) are reported. Their powder X-ray diffraction measurements and Rietveld analyzes show that they have the fluorite-related structures with space group Pnma (Ln=La, Pr, Nd), C222{sub 1} (Ln=Sm-Tb), or Fm-3m (Ln=Dy-Lu). Magnetic susceptibility measurements were carried out from 1.8 to 400 K. The Ln{sub 3}NbO{sub 7} compounds for Ln=Pr, Gd, Dy-Yb show Curie-Weiss paramagnetic behavior, and Sm{sub 3}NbO{sub 7} and Eu{sub 3}NbO{sub 7} show van Vleck paramagnetism. On the other hand, two magnetic anomalies were observed for both Nd{sub 3}NbO{sub 7} (0.6 and 2.7 K)more » and Tb{sub 3}NbO{sub 7} (2.0 and 3.2 K). From the results of specific heat measurements, it was found that these anomalies are due to the antiferromagnetic ordering of Ln ions in two different crystallographic sites (the 8-coordinated and 7-coordinated sites). - Ternary oxides Ln{sub 3}NbO{sub 7} (Ln=lanthanides) have the fluorite-related structures with space group Pnma (Ln=La, Pr, Nd), C222{sub 1} (Ln=Sm-Tb), or Fm-3m (Ln=Dy-Lu). In them, Nd{sub 3}NbO{sub 7} and Tb{sub 3}NbO{sub 7} show 'two-step' antiferromagnetic transitions due to the long-range antiferromagnetic ordering of Ln ions in different crystallographic sites.« less
  • Ternary rare earth antimonates Ln{sub 3}SbO{sub 7} (Ln=rare earths) were prepared and their structures were determined by X-ray diffraction measurements. They crystallize in an orthorhombic superstructure of cubic fluorite (space group Cmcm for Ln=La, Pr, Nd; C222{sub 1} for Ln=Nd-Lu), in which Ln{sup 3+} ions occupy two different crystallographic sites (the 8-coordinated and 7-coordinated sites). Their magnetic properties were characterized by magnetic susceptibility and specific heat measurements from 1.8 to 400 K. The Ln{sub 3}SbO{sub 7} (Ln=Nd, Gd-Ho) compounds show an antiferromagnetic transition at 2.2-3.2 K. Sm{sub 3}SbO{sub 7} and Eu{sub 3}SbO{sub 7} show van Vleck paramagnetism. Measurements of themore » specific heat down to 0.4 K for Gd{sub 3}SbO{sub 7} and the analysis of the magnetic specific heat indicate that the antiferromagnetic ordering of the 8-coordinated Gd ions occur at 2.6 K, and the 7-coordinated Gd ions order at a furthermore low temperature. - Graphical Abstract: Ternary rare earth antimonates Ln{sub 3}SbO{sub 7} (Ln=rare earths) crystallize in an orthorhombic superstructure of cubic fluorite (space group Cmcm for Ln=La, Pr, Nd; C222{sub 1} for Ln=Nd-Lu), in which Ln{sup 3+} ions occupy two different crystallographic sites (the 8-coordinated and 7-coordinated sites). Any of these compounds Ln{sub 3}SbO{sub 7} (Ln=Nd, Gd-Ho) shows an antiferromagnetic transition at 2.2-3.2 K.« less
  • Magnetic properties and structural transitions of ternary rare-earth transition-metal oxides Ln{sub 3}MO{sub 7} (Ln=rare earths, M=transition metals) were investigated. In this study, we prepared a series of molybdates Ln{sub 3}MoO{sub 7} (Ln=La-Gd). They crystallize in an orthorhombic superstructure of cubic fluorite with space group P2{sub 1}2{sub 1}2{sub 1}, in which Ln{sup 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{sub 1}2{sub 1}2{sub 1} to Pnma in the temperature range between 370 and 710 K. Their magnetic properties were characterized by magnetic susceptibility measurements frommore » 1.8 to 400 K and specific heat measurements from 0.4 to 400 K. Gd{sub 3}MoO{sub 7} shows an antiferromagnetic transition at 1.9 K. Measurements of the specific heat for Sm{sub 3}MoO{sub 7} 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 Ln{sub 3}MoO{sub 7} were compared with the magnetic properties and structural transitions of Ln{sub 3}MO{sub 7} (M=Nb, Ru, Sb, Ta, Re, Os, or Ir). -- Graphical Abstract: Magnetic properties and structural transitions of ternary rare-earth transition-metal oxides Ln{sub 3}MO{sub 7} (Ln=rare earths, M=transition metals) were investigated. In this study, we prepared a series of molybdates Ln{sub 3}MoO{sub 7} (Ln=La{approx}Gd). These compounds show a phase transition from the space group P2{sub 1}2{sub 1}2{sub 1} to Pnma in the temperature range between 370 and 710 K. Their magnetic properties were characterized by magnetic susceptibility and specific heat measurements from 0.4 to 400 K. The results of Ln{sub 3}MoO{sub 7} were compared with the magnetic properties and structural transitions of Ln{sub 3}MO{sub 7} (M=Nb, Ru, Sb, Ta, Re, Os, or Ir).« less