Synchrotron and neutron powder diffraction study of phase transition in weberite-type Nd{sub 3}NbO{sub 7} and La{sub 3}NbO{sub 7}

Nino, Juan C

doi:10.1016/j.jssc.2011.06.017

Title: Synchrotron and neutron powder diffraction study of phase transition in weberite-type Nd{sub 3}NbO{sub 7} and La{sub 3}NbO{sub 7}

Full Record
Other Related Research

Abstract

La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} are insulating compounds that have an orthorhombic weberite-type crystal structure and undergo a phase transition at about 360 and 450 K, respectively. The nature of the phase transitions was investigated via heat capacity measurements, synchrotron X-ray and neutron diffraction experiments. It is here shown that above the phase transition temperature, the compounds possess a weberite-type structure described by space group Cmcm (No. 63). Below the phase transition, the high temperature phase transforms into a weberite-type structure with space group Pmcn (No. 62). The phase transformation primarily involves the off-center shifting of Nb{sup 5+} ions inside the NbO{sub 6} octahedra, combined with shifts of one third of the Ln{sup 3+} (Ln{sup 3+}=La{sup 3+} and Nd{sup 3+}) ions at the center of the LnO{sub 8} polyhedra towards off-center positions. The phase transition was also proven to have great impacts on the dielectric properties. - Graphical abstract: The phase transition of La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} upon cooling primarily involves the off-center shifting of Nb{sup 5+} ions inside the NbO{sub 6} octahedra, combined with shifts of one third of the Ln{sup 3+} (Ln{sup 3+}=La{sup 3+} and Nd{sup 3+}) ions at the center of themore »« less

Authors:

Nino, Juan C ^[1]

Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States)

Publication Date:: Mon Aug 15 00:00:00 EDT 2011

OSTI Identifier:: 21580229

Resource Type:: Journal Article

Journal Name:: Journal of Solid State Chemistry

Additional Journal Information:: Journal Volume: 184; Journal Issue: 8; Other Information: DOI: 10.1016/j.jssc.2011.06.017; PII: S0022-4596(11)00343-4; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Journal ID: ISSN 0022-4596

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DIELECTRIC PROPERTIES; LANTHANUM IONS; NEODYMIUM IONS; NEUTRON DIFFRACTION; NIOBIUM IONS; ORTHORHOMBIC LATTICES; PHASE TRANSFORMATIONS; SPACE GROUPS; SPECIFIC HEAT; SYNCHROTRONS; TEMPERATURE RANGE 0400-1000 K; TRANSITION TEMPERATURE; X-RAY DIFFRACTION; ACCELERATORS; CHARGED PARTICLES; COHERENT SCATTERING; CRYSTAL LATTICES; CRYSTAL STRUCTURE; CYCLIC ACCELERATORS; DIFFRACTION; ELECTRICAL PROPERTIES; IONS; PHYSICAL PROPERTIES; SCATTERING; SYMMETRY GROUPS; TEMPERATURE RANGE; THERMODYNAMIC PROPERTIES

Citation Formats


                    Cai Lu, E-mail: cail@ornl.gov, and Nino, Juan C. Synchrotron and neutron powder diffraction study of phase transition in weberite-type Nd{sub 3}NbO{sub 7} and La{sub 3}NbO{sub 7}.  United States: N. p., 2011. 
        Web.  doi:10.1016/j.jssc.2011.06.017.

Copy to clipboard


                    Cai Lu, E-mail: cail@ornl.gov, & Nino, Juan C. Synchrotron and neutron powder diffraction study of phase transition in weberite-type Nd{sub 3}NbO{sub 7} and La{sub 3}NbO{sub 7}.  United States.  https://doi.org/10.1016/j.jssc.2011.06.017

Copy to clipboard


                    Cai Lu, E-mail: cail@ornl.gov, and Nino, Juan C. 2011.  
        "Synchrotron and neutron powder diffraction study of phase transition in weberite-type Nd{sub 3}NbO{sub 7} and La{sub 3}NbO{sub 7}".  United States.  https://doi.org/10.1016/j.jssc.2011.06.017.

Copy to clipboard


                    
@article{osti_21580229,

  title        = {Synchrotron and neutron powder diffraction study of phase transition in weberite-type Nd{sub 3}NbO{sub 7} and La{sub 3}NbO{sub 7}},

  author       = {Cai Lu, E-mail: cail@ornl.gov and Nino, Juan C},

  abstractNote = {La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} are insulating compounds that have an orthorhombic weberite-type crystal structure and undergo a phase transition at about 360 and 450 K, respectively. The nature of the phase transitions was investigated via heat capacity measurements, synchrotron X-ray and neutron diffraction experiments. It is here shown that above the phase transition temperature, the compounds possess a weberite-type structure described by space group Cmcm (No. 63). Below the phase transition, the high temperature phase transforms into a weberite-type structure with space group Pmcn (No. 62). The phase transformation primarily involves the off-center shifting of Nb{sup 5+} ions inside the NbO{sub 6} octahedra, combined with shifts of one third of the Ln{sup 3+} (Ln{sup 3+}=La{sup 3+} and Nd{sup 3+}) ions at the center of the LnO{sub 8} polyhedra towards off-center positions. The phase transition was also proven to have great impacts on the dielectric properties. - Graphical abstract: The phase transition of La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} upon cooling primarily involves the off-center shifting of Nb{sup 5+} ions inside the NbO{sub 6} octahedra, combined with shifts of one third of the Ln{sup 3+} (Ln{sup 3+}=La{sup 3+} and Nd{sup 3+}) ions at the center of the LnO{sub 8} polyhedra towards off-center positions. Above the phase transition temperature, Ln{sup 3+} and Nb{sup 5+} sit at a position with mirror symmetry and 2-fold axis. Below the phase transition temperature, Ln{sup 3+} and Nb{sup 5+} shift away from the 2-fold axis but still in the mirror plane. Highlights: > La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} exhibit a phase transition at 360 and 450 K, respectively. > The phase transformation primarily involves the off-center shifting of Nb{sup 5+} and Ln{sup 3+}. > The off-center ionic displacement decreases with increasing temperature. > Dielectric properties are greatly related to the off-center displacement.},

  doi          = {10.1016/j.jssc.2011.06.017},

  url          = {https://www.osti.gov/biblio/21580229},
  journal      = {Journal of Solid State Chemistry},

  issn         = {0022-4596},

  number       = 8,

  volume       = 184,

  place        = {United States},

  year         = {Mon Aug 15 00:00:00 EDT 2011},

  month        = {Mon Aug 15 00:00:00 EDT 2011}

}

Copy to clipboard

Journal Article:

https://doi.org/10.1016/j.jssc.2011.06.017

Other availability

Find in Google Scholar

Search WorldCat to find libraries that may hold this journal

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Synchrotron and neutron powder diffraction study of phase transition in weberite-type Nd[subscript 3]NbO[subscript 7] and La[subscript 3]NbO[subscript 7]

Journal Article Cai, Lu; Nino, Juan - J. Solid State Chem.

La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} are insulating compounds that have an orthorhombic weberite-type crystal structure and undergo a phase transition at about 360 and 450 K, respectively. The nature of the phase transitions was investigated via heat capacity measurements, synchrotron X-ray and neutron diffraction experiments. It is here shown that above the phase transition temperature, the compounds possess a weberite-type structure described by space group Cmcm (No. 63). Below the phase transition, the high temperature phase transforms into a weberite-type structure with space group Pmcn (No. 62). The phase transformation primarily involves the off-center shifting of Nb{sup 5+}more »« less
https://doi.org/10.1016/j.jssc.2011.06.017
Phase Transition in Weberite-Type Gd[subscript 3]NbO[subscript 7]

Journal Article Cai, Lu; Denev, Sava; Gopalan, Venkatraman; ... - J. Am. Ceram. Soc.

Gd{sub 3}NbO{sub 7} has an orthorhombic weberite-type crystal structure and undergoes a phase transition at about 340 K. The phase transition was confirmed by second harmonic generation, heat capacity measurement, and high-resolution X-ray diffraction. Above 340 K, Gd{sub 3}NbO{sub 7} has a centrosymmetric weberite-type structure with space group Cmcm (No. 63) and transforms at about 340 K into a non-centrosymmetric structure with space group Cm2m (No. 38). The phase transition is mainly due to off-center shifts of Nb{sub 5+} ions within NbO{sub 6} octahedra, as well as off-center shifts of one-third of the Gd{sup 3+} ions within GdO{sub 8} polyhedra.
https://doi.org/10.1111/j.1551-2916.2009.03494.x
A new uranyl niobate sheet in the cesium uranyl niobate Cs{sub 9}[(UO{sub 2}){sub 8}O{sub 4}(NbO{sub 5})(Nb{sub 2}O{sub 8}){sub 2}]

Journal Article Saad, S; Yagoubi, S; Renard, C; ... - Journal of Solid State Chemistry

A new cesium uranyl niobate, Cs{sub 9}[(UO{sub 2}){sub 8}O{sub 4}(NbO{sub 5})(Nb{sub 2}O{sub 8}){sub 2}] or Cs{sub 9}U{sub 8}Nb{sub 5}O{sub 41} has been synthesized by high-temperature solid-state reaction, using a mixture of U{sub 3}O{sub 8}, Cs{sub 2}CO{sub 3} and Nb{sub 2}O{sub 5}. Single crystals were obtained by incongruent melting of a starting mixture with metallic ratio=Cs/U/Nb=1/1/1. The crystal structure of the title compound was determined from single crystal X-ray diffraction data, and solved in the monoclinic system with the following crystallographic data: a=16.729(2) A, b=14.933(2) A, c=20.155(2) A{beta}=110.59(1){sup o}, P2{sub 1}/c space group and Z=4. The crystal structure was refined tomore »« less
https://doi.org/10.1016/j.jssc.2008.01.015
Interactions of Ba{sub 2}YCu{sub 3}O{sub 6+y} with the Gd{sub 3}NbO{sub 7} buffer layer in coated conductors

Journal Article Wong-Ng, W; Yang, Z; Kaduk, J; ... - Journal of Solid State Chemistry

A systematic study of the chemical interaction of Ba{sub 2}YCu{sub 3}O{sub 6+y} and Gd{sub 3}NbO{sub 7} was conducted under two processing conditions: purified air (21% p{sub o{sub 2}}), and 100 Pa p{sub o{sub 2}} (0.1% p{sub o{sub 2}}). Phases present along the pseudo-binary join Ba{sub 2}YCu{sub 3}O{sub 6z} and Gd{sub 3}NbO{sub 7} were found to be in two five-phase volumes within the BaO-1/2 Y{sub 2}O{sub 3}-1/2 Gd{sub 2}O{sub 3}-Nb{sub 2}O{sub 5}-CuO{sub y} system. Three common phases that are present in all samples are (Y,Gd){sub 2}Cu{sub 2}O{sub 5}, Ba(Y,Gd){sub 2}CuO{sub 5} and Cu{sub 2}O or CuO (depending on the processing conditions).more »« less
https://doi.org/10.1016/j.jssc.2010.01.006
Crystal structures and magnetic properties of fluorite-related oxides Ln{sub 3}NbO{sub 7} (Ln=lanthanides)

Journal Article Doi, Yoshihiro; Harada, Yuka; Hinatsu, Yukio - Journal of Solid State Chemistry

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 »« less
https://doi.org/10.1016/j.jssc.2008.12.012

Similar Records