Influence of La doping on structural and dielectric properties of SrBi{sub 2}Nb{sub 2}O{sub 9} ceramics

Journal Article · Thu Jan 15 04:00:00 EST 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3068368· OSTI ID:21185990

Verma, Maya; Sreenivas, K; Gupta, Vinay ^[1]

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1. Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

Lanthanum doped SrBi{sub 2}Nb{sub 2}O{sub 9} ceramics with the chemical formula SrBi{sub 2-x}La{sub x}Nb{sub 2}O{sub 9} (SBLN) (x=0-0.5) have been prepared through conventional solid state route. X-ray diffraction reveals the shrinkage of unit cell of strontium bismuth niobate with incorporation of La{sup 3+} dopant, having no lone pair electrons. Shifting of Raman phonon modes indicates the reduced rattling space of NbO{sub 6} octahedra with increase in La doping concentration. Further, the softening of lowest frequency phonon mode with increasing x in SBLN shows the transition from ferroelectric to paraelectric at room temperature. The dielectric properties for all the compositions are studied as a function of temperature (25 to 500 deg. C) over the frequency range of 10 kHz-1 MHz. With increase in lanthanum doping concentration the phase transition becomes diffused and transition temperature gets shifted toward lower temperature. A phase transition from normal ferroelectric to paraelectric has been observed via relaxor-type ferroelectrics with increase in x. The frequency dependence of transition temperature was studied in terms of Vogel-Fulcher relation for SBLN (x=0.4)

• OSTI ID: 21185990
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 2 Vol. 105; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BISMUTH COMPOUNDS
CERAMICS
DIELECTRIC PROPERTIES
DOPED MATERIALS
FERROELECTRIC MATERIALS
FREQUENCY DEPENDENCE
KHZ RANGE
LANTHANUM
LANTHANUM IONS
NIOBATES
PARAELECTRIC RESONANCE
PHASE TRANSFORMATIONS
PHONONS
RAMAN SPECTRA
STRONTIUM COMPOUNDS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TRANSITION TEMPERATURE
X-RAY DIFFRACTION