Structural characterization and Curie temperature determination of a sodium strontium niobate ferroelectric nanostructured powder

Journal Article · Sun May 15 04:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.03.001· OSTI ID:21504077

Lanfredi, Silvania; Genova, Diego H.M. ^[1]; Brito, Iara A.O. ^[2]; Lima, Alan R.F. ^[3]

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1. Faculdade de Ciencias e Tecnologia, FCT, Univ Estadual Paulista, UNESP, P.O Box 467, Presidente Prudente-SP (Brazil)
2. Instituto de Biociencias, Letras e Ciencias Exatas, Univ Estadual Paulista. UNESP, P.O Box 6154, Sao Jose do Rio Preto-SP (Brazil)
3. Departamento de Quimica, Univ Estadual de Ponta Grossa, UEPG, Ponta Grossa, PR (Brazil)

The Curie temperature and its correlation with the magnitude of the displacement of the niobium atom from the center of [NbO{sub 6}] octahedra in NaSr{sub 2}Nb{sub 5}O{sub 15} nanostructured powder were investigated. A single powder was prepared by high-energy ball milling. A powder with an average crystallite size of 37 nm was prepared by calcining the precursor at 1423 K. The refinement of the structural parameters was carried out by the Rietveld method. NaSr{sub 2}Nb{sub 5}O{sub 15} exhibits tetragonal symmetry with the tungsten bronze structure (a=b=12.3495 (6) A, c=3.8911 (2) A, V=593.432 (5) A{sup 3}, and Z=2). The site occupancy of the Na{sup +} and Sr{sup 2+} cations and the interatomic distances between the niobium and oxygen atoms were derived. The [NbO{sub 6}] octahedron undergoes both rotation and tilting depending on the crystallographic site. The Curie temperature of the powder was derived using both the impedance and infrared spectroscopy methods. -- Graphical abstract: Representation of the unit cell of the NaSr2Nb5O15 powder. Nb{sup 5+} cations are differentiated as Nb(I) and Nb(II). [Nb(I)O6] octahedral sites are represented by yellow color and [Nb(II)O6] by blue ones. Display Omitted highlights: > Spontaneous polarization has been based on the off-center displacement of atoms. > Distortion of the [Nb(II)O{sub 6}] octahedra occurs due to both to [NbO{sub 6}] octahedron rotation and tilting. > Newest another equation to derive the parameter Curie's temperature. > The ferroelectric transition in the NaSr{sub 2}NaNb{sub 5}O{sub 15} powder is of displacive type.

• OSTI ID: 21504077
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 5 Vol. 184; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
ALLOYS
CATIONS
CHARGED PARTICLES
COPPER ALLOYS
COPPER BASE ALLOYS
CRYSTALLOGRAPHY
CURIE POINT
DIELECTRIC MATERIALS
DISTANCE
FERROELECTRIC MATERIALS
IMPEDANCE
INFRARED SPECTRA
INTERATOMIC DISTANCES
IONS
MATERIALS
NANOSTRUCTURES
NIOBATES
NIOBIUM COMPOUNDS
NIOBIUM IONS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLARIZATION
POWDERS
REFRACTORY METAL COMPOUNDS
SODIUM IONS
SPECTRA
SPECTROSCOPY
STRONTIUM IONS
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT ALLOYS
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
TUNGSTEN ALLOYS
TUNGSTEN BRONZE