scholarly journals Ferroelectric Domain Studies of KNN Single Crystals by Piezo-force and Transmission Electron Microscopy

2012 ◽  
Vol 18 (S5) ◽  
pp. 113-114
Author(s):  
Muhammad Asif Rafiq ◽  
Maria Elisabete Costa ◽  
Paula Maria Vilarinho ◽  
Ian M Reaney
Keyword(s):  
Single Crystals ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Local Domain ◽  
Electromechanical Properties ◽  
As Doping ◽  
Transmission Electron ◽  
Alternative Materials ◽  
Electromechanical Performance ◽  
Monolithic Ceramics

Piezoelectric materials find important applications in micro- and nano-electromechanical systems (MEMS/NEMS). Pb(Zrx,Ti1-x)O3 (PZT) is currently the most widely used composition for such applications but due to environmental concerns over the toxicity of lead, lead free alternative materials are required. K0.5Na0.5NbO3 (KNN) is considered as a potential lead free piezoelectric but the current generation of monolithic ceramics has inferior electromechanical properties as compared to PZT. Consequently, there is great interest in improving the piezoelectric properties of KNN ceramics and various methods such as doping, hot-pressing and texturing are currently being studied. KNN single crystals like lead based single crystals have shown better electromechanical properties as compared to their ceramic counterparts. In addition, the behavior of a ferroelectric is largely dependent on its local domain response to an applied electrical or mechanical loading. Therefore, to understand better the material’s macroscopic properties, it is essential to access local ferroelectric domains behavior which collectively determines the electromechanical performance.

The Characteristic of the La3Ga5SiO14 Single Crystal Grown by Vertical Bridgman Method in Ar Atmosphere

2006 ◽  
Vol 510-511 ◽  
pp. 842-845 ◽  
Author(s):  
Noriko Bamba ◽  
Kentaro Kato ◽  
Toshinori Taishi ◽  
Takayuki Hayashi ◽  
Keigo Hoshikawa ◽  
...  
Keyword(s):  
Melting Point ◽  
Single Crystal ◽  
Single Crystals ◽  
Room Temperature ◽  
Color Change ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Piezoelectric Constant ◽  
Interstitial Oxygen ◽  
Vertical Bridgman

Langasite (La3Ga5SiO14: denoted by LGS) single crystal is one of the lead free piezoelectric materials with high piezoelectricity that is maintained up to its melting point (1470°C). Although LGS single crystals have usually been grown by Czochralski (CZ) method in oxygen contained atmosphere to prevent evaporation of Ga, they were grown by the vertical Bridgman (VB) method in Ar atmosphere without oxygen, and their properties were evaluated in this work. Transparent and colorless LGS single crystals were successfully obtained without Ga evaporation by the VB method in Ar atmosphere, and their resistivity at room temperature was much higher than that grown by conventional CZ method. Piezoelectric constant d11 of the crystal grown by the VB method was 6 x 10-12 C/N, which was close to that of the crystal grown by CZ method. The colorless transparent LGS single crystal turned to orange and its resistivity decreased by annealing in air. Since an orange-colored transparent LGS single crystal has been grown by conventional CZ method, this indicates that color change and the resistivity decrease of LGS crystal is caused by extra interstitial oxygen atoms in the crystal.

Development of Lead-Free Piezoelectric Materials Using Domain Wall Engineering

2006 ◽  
Vol 320 ◽  
pp. 151-154
Author(s):  
Satoshi Wada ◽  
Koichi Yako ◽  
Tomomitsu Muraishi ◽  
Hirofumi Kakemoto ◽  
Takaaki Tsurumi
Keyword(s):  
Barium Titanate ◽  
Domain Wall ◽  
Electric Field ◽  
Single Crystals ◽  
Electric Fields ◽  
Applied Electric Field ◽  
Piezoelectric Materials ◽  
Domain Size ◽  
Lead Free ◽  
Gradient Domain

For the [111] oriented barium titanate (BaTiO3) single crystals, the patterning electrode was applied to induce the finer engineered domain configurations with domain size of 3 2m. The poling treatment was performed at 134 °C under electric fields below 6 kV/cm to inhibit the burning of the patterning electrode with photoresist. As the results, the gradient domain sizes from 3 to 8-9 2m were induced into the 31 resonator. The d31 was measured at -243.2 pC/N, and this value was almost 70 % of the expected d31 of –337.7 pC/N for the resonator with domain size of 3 2m. This difference was originated from lower applied electric field below 6 kV/cm. However, this study was revealed that the patterning electrode was very powerful tool to induce much finer domain sizes below 5 2m.

Lead-free BNT-based composite materials: enhanced depolarization temperature and electromechanical behavior

2017 ◽  
Vol 46 (44) ◽  
pp. 15340-15353 ◽  
Author(s):  
Wangfeng Bai ◽  
Peng Zheng ◽  
Fei Wen ◽  
Jingji Zhang ◽  
Daqin Chen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Composite Materials ◽  
Solid Solutions ◽  
Lead Free ◽  
Practical Application ◽  
Electromechanical Properties ◽  
Depolarization Temperature ◽  
Electromechanical Behavior ◽  
Electromechanical Performance

The development of (Bi0.5Na0.5)TiO3-based solid solutions with both high depolarization temperature Td and excellent piezoelectric and electromechanical properties for practical application is intractable because improved thermal stability is usually accompanied by a deterioration in piezoelectric and electromechanical performance.

Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 86-87
Author(s):  
Kemining W. Yeh ◽  
Richard S. Muller ◽  
Wei-Kuo Wu ◽  
Jack Washburn
Keyword(s):  
Integrated Circuit ◽  
Acoustic Waves ◽  
New Technology ◽  
Surface Acoustic Waves ◽  
Electromechanical Properties ◽  
Leading Role ◽  
Saw Devices ◽  
Transmission Electron ◽  
High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

Precipitation of NiHfsi phase in NiAl single crystals containing Hf

1995 ◽  
Vol 53 ◽  
pp. 532-533
Author(s):  
A. Garg ◽  
R. D. Noebe ◽  
R. Darolia
Keyword(s):  
High Temperature ◽  
Single Crystals ◽  
High Temperature Strength ◽  
Bridgman Technique ◽  
Shell Mold ◽  
Third Phase ◽  
Unknown Phase ◽  
Transmission Electron ◽  
Two Phases ◽  
Nial Matrix

Small additions of Hf to NiAl produce a significant increase in the high-temperature strength of single crystals. Hf has a very limited solubility in NiAl and in the presence of Si, results in a high density of G-phase (Ni16Hf6Si7) cuboidal precipitates and some G-platelets in a NiAl matrix. These precipitates have a F.C.C structure and nucleate on {100}NiAl planes with almost perfect coherency and a cube-on-cube orientation-relationship (O.R.). However, G-phase is metastable and after prolonged aging at high temperature dissolves at the expense of a more stable Heusler (β'-Ni2AlHf) phase. In addition to these two phases, a third phase was shown to be present in a NiAl-0.3at. % Hf alloy, but was not previously identified (Fig. 4 of ref. 2 ). In this work, we report the morphology, crystal-structure, O.R., and stability of this unknown phase, which were determined using conventional and analytical transmission electron microscopy (TEM).Single crystals of NiAl containing 0.5at. % Hf were grown by a Bridgman technique. Chemical analysis indicated that these crystals also contained Si, which was not an intentional alloying addition but was picked up from the shell mold during directional solidification.

Transmission Electron Microscopy study of Bi-based superconducting phases

1990 ◽  
Vol 48 (4) ◽  
pp. 50-51
Author(s):  
J.G. Wen ◽  
K.K. Fung
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystals ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Space Groups ◽  
Superconducting Phases ◽  
Ceramic Samples ◽  
Transmission Electron ◽  
Modulated Structures

Bi-based superconducting phases have been found to be members of a structural series represented by Bi2Sr2Can−1Cun−1On+4, n=1,2,3, and are referred to as 2201, 2212, 2223 phases. All these phases are incommensurate modulated structures. The super space groups are P2/b, NBbmb 2201, 2212 phases respectively. Pb-doped ceramic samples and single crystals and Y-doped single crystals have been studied by transmission electron microscopy.Modulated structures of all Bi-based superconducting phases are in b-c plane, therefore, it is the best way to determine modulated structure and c parameter in diffraction pattern. FIG. 1,2,3 show diffraction patterns of three kinds of modulations in Pb-doped ceramic samples. Energy dispersive X-ray analysis (EDAX) confirms the presence of Pb in the three modulated structures. Parameters c are 3 0.06, 38.29, 30.24Å, ie 2212, 2223, 2212 phases for FIG. 1,2,3 respectively. Their average space groups are all Bbmb.

Studies on the Temperature Stability of Pure and Doped Triglycine Sulphate Crystals Using TGA/DTA

2020 ◽  
Vol 10 (3) ◽  
pp. 206-212
Author(s):  
Vijeesh Padmanabhan ◽  
Maneesha P. Madhu ◽  
Supriya M. Hariharan
Keyword(s):  
Thermal Analysis ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Temperature Stability ◽  
Bandgap Energy ◽  
Dsc Analysis ◽  
Slow Cooling ◽  
As Doping ◽  
Similar Dependence ◽  
Temperature Ranges

Aim: To study the temperature stability of TGS doped with ZnSO4, CdCl2, BaCl2, and compare it with that of pure TGS. Objectives: Synthesizing pure and doped TGS and studying their temperature dependence using TGA, DTA, and DSC analysis. Methods: Slow cooling solution growth was used to grow single crystals of pure and doped TGS. The TGA, DTA and DSC analysis was conducted for determining the temperature stability. Results: The thermal analysis of pure and doped TGS shows that the doped samples show a similar dependence on temperature as pure TGS. The temperature of decomposition of pure and doped samples (BTGS, ZTGS, CdTGS) was 226.60°C, 228.38°C, 229.13°C, and 239.13°C respectively. The melting onset of these samples was 214.51°C, 216.04°C, 217.69°C and 216.04°C respectively. Conclusion: The study shows that doping TGS with the above three described materials did not alter their temperature stability considerably. It is a good result as doping TGS, for varying its characteristics like absorbance, reflectance, bandgap energy, etc., which did not alter its temperature stability. Therefore, TGS doped with the above three dopants can be used at the same temperature ranges as of pure TGS but with much-improved efficiency.

scholarly journals Lead-free halide perovskite Cs3Bi2Br9 single crystals for high-performance X-ray detection

2021 ◽  
Author(s):  
Xiang Li ◽  
Xinyuan Du ◽  
Peng Zhang ◽  
Yunqiu Hua ◽  
Lin Liu ◽  
...  
Keyword(s):  
Single Crystals ◽  
High Performance ◽  
Lead Free ◽  
X Ray ◽  
Halide Perovskite

Temperature-induced phase transition of -oriented 0.92Na0.5Bi0.5TiO3-0.08Bi(Zn0.5Ti0.5)O3 lead-free single crystals

2021 ◽  
Author(s):  
Junjie Xiao ◽  
Sixing Liu ◽  
Jushan Wang ◽  
Jialin Xu ◽  
Zhang Zhang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Single Crystals ◽  
Lead Free
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