Stability of rhombohedral structure and improved dielectric and ferroelectric properties of Ba, Na, Ti doped BiFeO3 solid solutions

2014 ◽

Vol 70 (a1) ◽

pp. C1522-C1522

Author(s):

Peter Blanchard ◽

Brendan Kennedy ◽

Chris Ling

Keyword(s):

Solid Solutions ◽

Structural Changes ◽

Structural Evolution ◽

Rhombohedral Phase ◽

Rhombohedral Structure ◽

Electronic Effects ◽

Spectra Analysis ◽

Space Group ◽

Industry Standard ◽

Made In

Significant efforts have been made in the development of (Bi0.5Na0.5)TiO3 ferroelectrics as an alternative to the lead-based industry standard PbTi1-xZrxO3.[1] It has also been shown that doping the A- and B-site of (Bi0.5Na0.5)TiO3 can greatly improve the ferroelectric behavior of these materials,[2] possibly due to the formation of two or more ferroelectric phases at a morphotropic phase boundary (MPB). As such, there is a significant interest in understanding the structural changes in (Bi0.5Na0.5)TiO3-based solid solutions. (Bi0.5Na0.5)TiO3 was originally described as adopting a rhombohedral structure in space group R3c, However, the accuracy of this description has been greatly debated. It was recently suggested that (Bi0.5Na0.5)TiO3 actually adopts a monoclinic structure in space group Cc.[3] Given this recent controversy, we investigated the structural evolution of (Bi0.5Na0.5)TiO3-based solid solutions, particularly the (Bi0.5Na0.5)Ti1-xZrxO3 and (1-x)(Bi0.5Na0.5)TiO3–xBiFeO3 solid solutions., using both diffraction and spectroscopy techniques. Diffraction measurements on (Bi0.5Na0.5)TiO3 confirm that both monoclinic Cc and rhombohedral R3c phases are present at room temperature. Diffraction analysis showed that doping (Bi0.5Na0.5)TiO3 with a small amount of (Bi0.5Na0.5)ZrO3 and BiFeO3 can stabilizes the rhombohedral phase. The Ti/Fe K-edge and Zr L3-edge XANES spectra analysis was performed to determine the effects doping has on the local displacement of the B-site cations.

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The Influences of NaNbO3 on the Dielectric and Structure Characteristics of (1-X) (Na0.5Bi0.5)TiO3–x NaNbO3 Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.415-417.1064 ◽

2011 ◽

Vol 415-417 ◽

pp. 1064-1069 ◽

Cited By ~ 1

Author(s):

Chia Ching Wu ◽

Ying Hsun Lin ◽

Ping Shou Cheng ◽

Chao Chin Chan ◽

Cheng Fu Yang

Keyword(s):

Dielectric Constant ◽

Ferroelectric Properties ◽

Rhombohedral Structure ◽

X Ray Diffraction ◽

Depolarization Temperature ◽

Dielectric Characteristics ◽

X Ray ◽

Maximum Dielectric Constant ◽

Second Phases ◽

Xrd Patterns

Perovskite-based (1-x) (Na0.5Bi0.5)TiO3-x NaNbO3 [(1-x) NBT-x NN, x = 0.1, 0.2, 0.3 and 0.4] ceramics were sintered at 1080°C. Dielectric characteristics, crystalline structures, and Raman investigations were carried out on (1-x) (Na0.5Bi0.5)TiO3-x NaNbO3 ceramics. X-ray diffraction (XRD) patterns showed that NaNbO3 ceramic would form a solid solution with (Na0.5Bi0.5)TiO3 ceramic, and and unknown or second phases were not observable as well. NaNbO3 ceramic diffused into the crystalline structure of (Na0.5Bi0.5)TiO3 ceramic and (1-x) NBT-x NN ceramics still revealed a rhombohedral structure. The temperature-dielectric constant curves showed that as NN content increased, the temperature to reveal the maximum dielectric constant (Tm) was raised, the depolarization temperature (Td) was shifted to lower value, and the dielectric constant at Tm and the loss tangent at Td gradually decreased. The Raman bands at 770 and 830 cm-1 were attributed to the existence of the oxygen vacancies. In this study, the relaxor-type ferroelectric properties of NBT ceramic had been improved as NN ceramic was added.

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Effect of Barium Titanate Additives on Dielectric Property of PLZT Ceramics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.804.21 ◽

2015 ◽

Vol 804 ◽

pp. 21-24

Author(s):

Ladapak Chumprasert ◽

Narit Funsueb ◽

Apichart Limpichaipanit ◽

Athipong Ngamjarurojana

Keyword(s):

Barium Titanate ◽

Lead Zirconate Titanate ◽

Perovskite Phase ◽

Ferroelectric Properties ◽

Lead Zirconate ◽

Dielectric Behavior ◽

Rhombohedral Structure ◽

Soaking Time ◽

Oxide Powders ◽

Formation And Evolution

Barium titanate (BT) additive in lanthanum modified lead zirconate titanate (PLZT) was used to modify the microstructure and resultant properties of (1-x) PLZT– x BT where x= 0, 0.05, 0.10, 0.15, 0.20 and 0.25. Oxide powders were synthesized by mixed oxide synthetic route via a rapid vibro-milling technique. All of samples were sintered at 1275°C with the soaking time of 4 h. The ceramic samples were investigated for phase formation and evolution, dielectric behavior and ferroelectric properties. Introduction of BT in PLZT lattice resulted in ferroelectric tetragonal-rhombohedral structure, and further increase of BT content resulted in stabilizing the ferroelectric tetragonal perovskite phase. Dielectric behavior and ferroelectric properties were examined as a function of BT content.

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Diffuse Phase Transition and Ferroelectric Properties of Ceramic Solid Solutions in New SrTiO3-BiScO3 System

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.67.59 ◽

2010 ◽

Vol 67 ◽

pp. 59-63 ◽

Cited By ~ 3

Author(s):

Oleg Ivanov ◽

Elena Danshina ◽

Yulia Tuchina ◽

Viacheslav Sirota

Keyword(s):

Solid Solutions ◽

Ferroelectric Properties ◽

Hysteresis Loops ◽

Ferroelectric Materials ◽

X Ray Diffraction ◽

Weakly Nonlinear ◽

Nonlinear Hysteresis ◽

Processing Techniques ◽

First Time ◽

Diffuse Phase

Ceramic solid solutions of (1-x)SrTiO3-(x)BiScO3 system with x=0, 0.05, 0.1, 0.2, 0.3, 0.4 and 0.5 have been for the first time synthesized via solid-state processing techniques. Both of end compounds in this system are not ferroelectric materials. X-ray diffraction analysis revealed that at room temperature the samples under study at x=0.2, 0.3, 0.4 and 0.5 consist of mixture of center-symmetric cubic Pm3m phase and polar tetragonal P4mm phase. Anomalous behaviour of dielectric permittivity and dielectric losses for these samples is found to be specific one for ferroelectrics with diffuse phase transitions. Furthermore, examination of the polarization hysteresis behavior revealed weakly nonlinear hysteresis loops in the ferroelectric phase.

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