New methods for the preparation and dielectric properties of La{sub 2−x}Sr{sub x}NiO{sub 4} (x = 1/8) ceramic

Journal Article · Sun May 15 00:00:00 EDT 2016 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2016.01.023· OSTI ID:22581539

Kadyrova, N. I. ^[1]; Melnikova, N. V. ^[2]; Gyrdasova, O. I. ^[1]; Yakovleva, E. A. ^[2]; Zainulin, Yu. G. ^[1]

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1. Institute of Solid State Chemistry, UB RAS, 91, Pervomaiskaya str., Ekaterinburg 620990 (Russian Federation)
2. Ural Federal University, 19, Mira str., Ekaterinburg (Russian Federation)

Highlights: • A new fuel in solution combustion synthesis of fine powder La{sub 15/8}Sr{sub 1/8}NiO{sub 4}. • Changes in the morphology of the ceramic La{sub 15/8}Sr{sub 1/8}NiO{sub 4} after thermobaric treatment. • Changes in structural parameters of the La{sub 15/8}Sr{sub 1/8}NiO{sub 4} after thermobaric treatment. • Increase of the dielectric constant of the thermobaric treated ceramic La{sub 15/8}Sr{sub 1/8}NiO{sub 4}. • Using of dielectric modulus and impedance formalisms, of equivalent circuits method. - Abstract: The perovskite-type oxide La{sub 2−x}Sr{sub x}NiO{sub 4} (x = 1/8) was prepared by a new precursor route. The reaction proceeds in the self-ignition mode. Single-phase powder and gas-tight ceramic samples can be produced by single annealing of decomposition products. It was shown that as a result of thermobaric treatment of La{sub 2−x}Sr{sub x}NiO{sub 4} (x = 1/8) the solid solution La{sub 2−x}Sr{sub x}NiO{sub 4} with a higher concentration of strontium and the second phase La{sub 3}Ni{sub 2}O{sub 7} are formed. Short-term (5 min) thermobaric treatment (P = 2.5 GPa) at t° = 900 °C changes the unit cell parameters, but is not accompanied by structural transitions. At the same time, morphological restructuring of the sample occurs—the agglomerates delaminate into thin plates crystals. It was established that the permittivity of the material exposed to thermobaric treatment is much higher compared to that of the sample annealed at atmospheric pressure and virtually does not depend on frequency in a wide temperature range.

• OSTI ID: 22581539
• Journal Information: Materials Research Bulletin, Vol. 77; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CERAMICS
COMBUSTION
CONCENTRATION RATIO
CRYSTALS
DECOMPOSITION
DIELECTRIC MATERIALS
IMPEDANCE
LANTHANUM COMPOUNDS
MORPHOLOGY
NIOBATES
PERMITTIVITY
PRESSURE RANGE GIGA PA
SILVER CARBONATES
SOLID SOLUTIONS
STRONTIUM
STRONTIUM COMPOUNDS
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION