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Structural phase transition, impedance spectroscopy and narrow optical band Gap in (1-x)KNbO3-x Ba(Sc1/2Nb1/2) O-3

IR@NPL: CSIR-National Physical Laboratory, New Delhi

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Title Structural phase transition, impedance spectroscopy and narrow optical band Gap in (1-x)KNbO3-x Ba(Sc1/2Nb1/2) O-3
 
Creator Tiwari, Rajender Prasad
Kumar, Vijay
Singh, S.
Shah, Jyoti
Kotnala, Ravinder Kumar
Birajdar, Balaji
 
Subject Materials Science
 
Description In the progress of exploring lead-free ferroelectric perovskites, a new solid solution of (1-x) KNbO3-x Ba(Sci Nbl) O-3 is synthesized using solid state method. The effect of Ba and Sc codoping on structural phase transition, dielectric, ferroelectric, electrical, and optical properties is systematically studied. A narrow band gap of 1.98eV is observed at x = 0.05. On further increase in x, the optical band gap increases due to increased strain. The crystal symmetry changes from orthorhombic at x = 0.00 to tetragonal phase at x <= 0.15, remains in pseudocubic phase for 0.15 < x < 0.35, and finally transforms to the cubic symmetry at x >= 0.35. A new Raman active mode evolves at 180 cm(-1) at x = 0.15, which could be the TO or LO phonon of A(1) symmetry. The electrical microstructure of the prepared electroceramics at room temperature has been investigated using impedance spectroscopy. This newly synthesized ferroelectric perovskite material has promising potential applications for photocatalysis and photovoltaics, especially under the visible light spectrum.
 
Publisher Elsevier
 
Date 2018-04
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://npl.csircentral.net/4007/1/Structural%20phase%20transition%2C%20impedance%20spectroscopy.pdf
Tiwari, Rajender Prasad and Kumar, Vijay and Singh, S. and Shah, Jyoti and Kotnala, Ravinder Kumar and Birajdar, Balaji (2018) Structural phase transition, impedance spectroscopy and narrow optical band Gap in (1-x)KNbO3-x Ba(Sc1/2Nb1/2) O-3. Journal of the European Ceramic Society , 38 (4). pp. 1427-1433. ISSN 0955-2219
 
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