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.

RBS/Channeling Characterization of Ba Implanted Mg

1992 ◽  
Vol 279 ◽  
Author(s):  
R. C. Da Silva ◽  
Th. Hauser ◽  
A. A. Melo ◽  
J. C. Soares ◽  
M. F. Da Silva ◽  
...  
Keyword(s):  
Melting Point ◽  
Single Crystal ◽  
Room Temperature ◽  
Surface Segregation

ABSTRACTThe behaviour of 300 keV Ba ions implanted at room temperature with doses between 1015 and 1017 cm−2 in Mg single crystal and foils was investigated. The results show that the Ba ions do not occupy substitutions sites in Mg, either after the implantation or the annealing treatments. However, pronounced migration of Ba to the surface is observed above 380 °C. The remaining fraction overlaps with the aa-implanted distribution and forms small precipitates. This behaviour is not correlated with the recovery of the Mg lattice which is already complete at about 250 °C. The surface segregation of Ba delays the evaporation of Mg to temperatures near the melting point.

Enhanced fatigue resistance and lattice dynamics induced by the strong local strain in Fe-doped KTa1-xNbxO3 single crystal

2021 ◽  
Author(s):  
Xiaolin Huang ◽  
Peng Tan ◽  
Yu Wang ◽  
Yao Zhang ◽  
Xiangda Meng ◽  
...  
Keyword(s):  
Single Crystal ◽  
Fatigue Resistance ◽  
Lattice Dynamics ◽  
Piezoelectric Materials ◽  
Local Strain ◽  
Lead Free ◽  
Fatigue Properties ◽  
Practical Applications ◽  
Local Structures ◽  
The Impact

Improvement of durability is greatly important for the practical applications of lead-free-doped piezoelectric materials. However, the promotional mechanism of anti-fatigue properties and the impact on local structures from ion dopants...

scholarly journals The critical shear stress of mercury single crystals

1937 ◽  
Vol 163 (912) ◽  
pp. 34-53 ◽  
Keyword(s):  
Plastic Deformation ◽  
Shear Stress ◽  
Melting Point ◽  
Single Crystal ◽  
Single Crystals ◽  
Critical Shear Stress ◽  
Impurity Content ◽  
Thermal Agitation ◽  
Plastic Yield ◽  
Metal Single Crystals

The influence of very small quantities of impurity on the critical shear stress of metal single crystals has an important bearing on the mechanism of their plastic deformation. For investigations in this field, mercury is a very suitable metal: its impurity content can easily be reduced to an extremely low level (Hulett 1911) and it contains no dissolved gases (Hulett 1911). Also, as first pointed out by Andrade (1914), single crystal wires of this metal can be prepared without difficulty. The low melting point of mercury (-38∙8° C.) is far from being a disadvantage. The crystals can be maintained at -60° C., and at a temperature so near the melting point the thermal agitation may be expected to accentuate phenomena not observable at lower temperatures, if such agitation plays the important part in the mechanism of glide ascribed to it (Taylor 1934; Polanyi 1934; Orowan 1934). As a possible instance of this, the experiments to be described have revealed the existence of a preliminary “set” preceding the true plastic yield. Widely differing forms of slip band have also been observed, and are described elsewhere (Greenland 1937). It is hoped that these results will throw further light on the mechanism of glide.

Characteristic Investigations of Stoichiometric LiNbO3 Single Crystal Fiber Co-Doped with Tb and Mn

2004 ◽  
Vol 449-452 ◽  
pp. 985-988
Author(s):  
S.M. Lee ◽  
J.W. Shur ◽  
T.I. Shin ◽  
W.S. Yang ◽  
G.Y. Kim ◽  
...  
Keyword(s):  
Absorption Band ◽  
Single Crystal ◽  
Optical Microscopy ◽  
Single Crystals ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Crystal Fiber ◽  
Ft Ir ◽  
Homogeneous Distributions ◽  
Co Doped

[MnO2(1.0mol%) : Tb4O7(0.5mo%)] doped stoichiometric LiNbO3 (Mn:Tb:SLN) single crystals of 0.5~1.0 mm in diameter and 30~35 mm in length were grown by micro pulling down(µ-PD) method. We investigated the photoluminescence (PL) properties of Mn:Tb:SLN single crystal. The OH- absorption band of the single crystals observed infrared the absorption spectra by using an FT-IR spectrophotometer at room temperature. Homogeneous distributions of Mn and Tb concentration were confirmed by the EPMA and observed defects by optical microscopy.

Electrical Transport Properties of the Pentatelluride Materials Hfte5 and Zrte5

1997 ◽  
Vol 478 ◽  
Author(s):  
T. M. Tritt ◽  
M. L. Wilson ◽  
R. L. Littleton ◽  
C. Feger ◽  
J. Kolis ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Electrical Transport ◽  
Entire Range ◽  
Room Temperature ◽  
Polycrystalline Material ◽  
Polycrystalline Materials ◽  
Electrical Transport Properties ◽  
Low Dimensional ◽  
P Type

AbstractWe have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe5 and ZrTe5. We have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, Tp where Tp ≈ 80K for HfTe5 and Tp ≈ 145K for ZrTe5. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. This data is similar to behavior observed previously in these materials. We have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe5 and ZrTe5. We have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 μV/K and +65 μV/K for HfTe5 and ZrTe5 respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 μV/K for HfTe5 and +35 μV/K for ZrTe5. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T ≈ 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 mΩ-cm and 24 mΩ-cm for Hfre5 and ZrTe5 respectively, compared to single crystal values of 0.35 mΩ-cm (HfTe5) and 1.0 mΩ-cm (ZrTe5). We have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. We will discuss these materials in relation to their potential as candidates for thermoelectric applications.

Ion Induced Damage and their Annealing in LiTaO3 Single Crystal

1995 ◽  
Vol 396 ◽  
Author(s):  
Z Zhang ◽  
I.A. Rusakova ◽  
W.K. Chu
Keyword(s):  
Curie Temperature ◽  
Single Crystal ◽  
Single Crystals ◽  
Thermal Annealing ◽  
Crystalline Structure ◽  
Room Temperature ◽  
Complete Recovery ◽  
Oxygen Ions ◽  
Annealing Temperatures ◽  
Crystal Interface

AbstractLiTaO3 single crystals have been implanted with 100 keV oxygen ions at room temperature with doses of 1×1014 /cm2,6xl014/cm2,1.2x1015/cm2, 6xl015/cm2, and 2xl016/cm2. Annealing temperatures ranged from 550 °C to 1075 °C. RBS-channeling and TEM were used for characterization. For partially damaged samples, complete recovery of the crystalline structure was achieved after annealing at 550 °C, which is below the Curie temperature. For totally amorphized samples, thermal annealing induced multidomain growth. These domains extend beyond the original amorphous/crystal interface deep into bulk (1 – 1.5 μm ).

SINGLE CRYSTAL GROWTH AND TEXTURING OF LEAD-BASED PIEZOELECTRIC CERAMICS VIA TEMPLATED GRAIN GROWTH PROCESS

2008 ◽  
Vol 01 (02) ◽  
pp. 127-132 ◽  
Author(s):  
THOMAS RICHTER ◽  
CARSTEN SCHUH ◽  
RALF MOOS ◽  
ENDER SUVACI
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystals ◽  
Grain Growth ◽  
High Performance ◽  
Piezoelectric Materials ◽  
Secondary Recrystallization ◽  
Single Crystal Growth ◽  
Templated Grain Growth ◽  
Textured Ceramics

In the field of high-performance piezoelectric materials, PMN-PT single crystals and textured ceramics have been attracting increased research interest for several years. On the other hand, the growth of single crystals from melt for PZT-based compositions is impossible due to its incongruent melting behavior. In order to obtain the characteristics of pure single crystal PZT as closely as possible, the PZT must be textured by secondary recrystallization of introduced seeds in a fine-grained matrix. Zirconium was therefore added to a PMN-PT-ceramic with 32 mol% PT ( Pb ( Mg 1/3 Nb 2/3)0.68 Ti 0.32 O 3) in order to obtain a PMN-PZT-ceramic with 37 mol% PT and 21 mol% PZ ( Pb ( Mg 1/3 Nb 2/3)0.42( Ti 0.638 Zr 0.362)0.58 O 3). Initially, the growth mechanism of (001)-oriented BaTiO 3 (BT) single crystals in those matrices was investigated. The piezoelectric single crystals were produced via a process that starts with the hot pressing of a BT single crystal in cold isostatically pressed ceramics, followed by an additional sintering step in order to achieve a secondary recrystallization. The measured growth lengths in PMN-PT and PMN-PZT matrices were up to 140 μm and 65 μm, respectively. Having developed this understanding, both ceramics were textured via the templated grain growth (TGG) process by using (001)-oriented BT templates. Sintering of templated grain bodies resulted in template growth into the matrix to produce textured ceramics with Lotgering factors up to 0.99 for both compositions. In textured samples unipolar strain s33 was enhanced by a factor of up to 1.8 compared to randomly oriented ceramics. By contrast, BT single crystal growth in an alternative PZT matrix with NdMn doping was not successful. Hence, in the present work, growth experiments in this NdMn -doped PZT were first performed using PZT fibers of similar composition as seeds. Growth of the fiber diameter of up to 100 μm was observed in that matrix.

The crystal structure of a simple enol formed in a single-crystal-to-single-crystal enolene rearrangement

2004 ◽  
Vol 82 (2) ◽  
pp. 301-305 ◽  
Author(s):  
Kenneth CW Chong ◽  
Brian O Patrick ◽  
John R Scheffer
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
Room Temperature ◽  
Thermal Reaction ◽  
Thermal Rearrangement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phenyl Ketone

When crystals of 9-tricyclo[4.4.1.0]undecalyl-4-(carbomethoxy)phenyl ketone (1) were allowed to stand in the dark for extended periods of time at room temperature, the compound underwent a thermal reaction — the enolene rearrangement — to afford enol 2. The crystals remained transparent and appeared unchanged in shape as the reaction proceeded. X-ray diffraction data were collected on single crystals containing 17%, 25%, 66%, and 100% of the enol. The crystal structure of a simple enol was obtained via this novel single-crystal-to-single-crystal enolene rearrangement.Key words: single crystal, thermal, rearrangement, enol, enolene.

GROWTH OF 4-(4-DIMETHYLAMINOSTYRYL)-1-METHYLPYRIDINIUM TOSYLATE (DAST) MIXED SINGLE CRYSTAL BY BRIDGMAN–STOCKBARGER METHOD

2004 ◽  
Vol 13 (03n04) ◽  
pp. 359-366
Author(s):  
P. M. USHASREE ◽  
T. MIDORIKAWA ◽  
K. KOMATSU ◽  
T. KAINO
Keyword(s):  
Melting Point ◽  
Single Crystal ◽  
Nonlinear Optical ◽  
Mixed Crystal ◽  
Molten State ◽  
Vertical Bridgman ◽  
Stockbarger Method ◽  
Optical Applications ◽  
Nonlinear Optical Applications

4-(4-dimethylaminostyryl)-1-methylpyridinium tosylate (DAST) is a very promising organic nonlinear optical (NLO) material for future optoelectronic and nonlinear optical applications, though it cannot be grown from molten state. Hence, a derivative of DAST was synthesized and mixed with DAST. The melting point of the mixed crystal decreased drastically, making it possible to grow a single crystal from molten state. In the present investigation, a mixed single crystal of DAST has been grown from molten state by vertical Bridgman–Stockbarger method.

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