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Title: Investigations of structural dielectric and electrical properties of rare earth doped layered ferroelectric ceramics
Researcher: Kannan B, Rajesh
Guide(s): Venkataraman, B. Harihara
Keywords: Structural, Dielectric, Electrical Properties, Layered, Ferroelectric, Ceramics
University: Birla Institute of Technology and Science
Completed Date: 
Abstract: In recent years, bismuth layered ferroelectric materials such as SrBi2Ta2O9 (SBT), BaBi2Nb2O9 (BBN), Bi4Ti3O12 (BIT) and SrBi2Nb2O9 (SBN) have attracted much attention due to its potential applications in nonvolatile random access memory (NVRAM) devices. Lead zirconate titanate, PbZrTiO3 (PZT) was the prominent material for the NVRAM application owing to its low switching field, high remnant polarization and low processing temperature. However, the PZT material undergoes severe fatigue failure and retention loss on conventional silicon substrate with platinum (Pt) electrodes. The renewed interest stems from the Aurivillius family of layered ferroelectric materials (e.g. SBT, BBN, BIT, and SBN) because of their fatigue-free behavior and low coercive field. But the drawbacks of these layered ferroelectric materials are low remnant polarization, high processing temperature and high dc conductivity. It was known that the physical properties of these layered ferroelectric materials could be enhanced by doping the suitable cations in the crystal lattice. The emergence of lanthanum ion doped bismuth titanate has fuelled considerable interest to investigate the influence of trivalent rare earth ions on the physical properties of bismuth based layered ferroelectric compounds. It is widely accepted that the Bi2O2 layers have a significant influence on the polar and electrical conductivity properties of bismuth based layered structures. It is expected that by substituting Bi3+ (ionic radius = 0.103 nm) ion with a slightly smaller rare earth cation such as Sm3+ ion (ionic radius = 0.098 nm) could significantly increase the structural distortion in the crystal structure and thereby enhancing the polar properties. However, the studies are limited concerning the improvement of dielectric properties of the layered perovskite ferroelectrics such as SBT and BBN through the substitution of Bi3+ ions in Bi2O2 layer by samarium ion (Sm3+). Molten salt synthesis (MSS) is one of the effective routes for synthesizing ceramic powders at
Pagination: xi
Appears in Departments:Physics

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