Formation of Nd1+x (Ba1−ySry)2−x Cu3O7±δ solid solutions by crystal pulling

2001 ◽  
Vol 16 (2) ◽  
pp. 529-533 ◽  
Author(s):  
Xin Yao ◽  
E. A. Goodilin ◽  
Teruo Izumi ◽  
Yuh Shiohara
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Solid Solutions ◽  
Liquid Composition ◽  
The Other ◽  
Composition Control ◽  
Structure Control ◽  
Structure Relation ◽  
Rich Liquid ◽  
Nd Substitution

With the addition of Sr into the NdO1.5–BaO–CuOz flux, series single crystals of Nd1+x (Ba1−ySry)2−x Cu3O7±δ solid solutions (Nd1113ss) were successfully grown by crystal pulling. The liquid composition control was of key importance for controlling the crystal composition, which led to a fundamental structure control. The tetragonal Nd1113ss structure was readily obtained, using a Ba-poor liquid, due to a higher Sr liquid solubility, or using a liquid with the Ba/Cu ratio around 0.33. On the other hand, a Ba-rich liquid could effectively suppress the Nd substitution at Ba sites. The higher Sr addition for achieving a stoichiometric Nd1113 compound was thermodynamically prohibited by (i) an inherently low Sr liquid solubility and (ii) the formation of BaSrCu2Oz phase in the flux at the temperature range for crystal growth. The liquid-solid-structure relation was studied.

Crystal growth of YBa2Cu3O7 by the SRL-CP method under low oxygen partial pressure atmosphere

1994 ◽  
Vol 9 (8) ◽  
pp. 1946-1951 ◽  
Author(s):  
M. Nakamura ◽  
Y. Yamada ◽  
Y. Shiohara
Keyword(s):  
Crystal Growth ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Single Crystals ◽  
Oxygen Pressure ◽  
Crystal Surface ◽  
Nitrogen Atmosphere ◽  
Low Oxygen ◽  
Pure Nitrogen ◽  
Rich Liquid

Single crystals of YBa2Cu3O7−x (Y123) were grown by a modified top-seeded crystal pulling method using a BaO-CuO solution with the solid Y2BaCuO5 (Y211) as a solute in an yttria crucible [the so-called solute-rich liquid crystal pulling (SRL-CP) method] under 2% oxygen partial pressure atmosphere [P(O2) = 0.02 atm]. According to the pseudo-binary phase diagrams of Lee and Lee,1 the temperature of Y123 crystal growth was expected to be lower for 0.02 atm oxygen pressure than for 0.21 atm oxygen pressure. The single crystals grown under P(O2) = 0.02 atm and cooled under the same atmosphere after the separation of crystal from a solution had twins near the microcracks on the crystal surface. On the other hand, the single crystals grown under P(O2) = 0.02 atm and cooled under pure nitrogen atmosphere (6N) showed no twin structure. These results indicate that twins did not form during crystal growth but formed due to tetragonal-orthorhombic transition as a consequence of oxygenation at cooling under low oxygen partial pressure.

YBa2Cu3O7−x single-crystal growth by the pulling method with crystal rotation effect control

1995 ◽  
Vol 10 (7) ◽  
pp. 1593-1600 ◽  
Author(s):  
Y. Namikawa ◽  
M. Egami ◽  
Y. Yamada ◽  
Y. Shiohara
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystals ◽  
Forced Convection ◽  
Rotation Rate ◽  
Growth Interface ◽  
Crystal Rotation ◽  
Crystal Diameter ◽  
Rich Liquid ◽  
Floating Particles

YBa2Cu3C7−x (Y123) single crystals have been grown by the modified pulling method (Solute Rich Liquid Crystal Pulling method, SRL-CP). For further superconductor device application, it is important to establish a technique that enables us to produce larger Y123 single crystals consistently. We have investigated the relationship among the crystal size, the crystal rotation rate, the flow pattern in the melt, and the temperature at the crystal growth interface experimentally. Increase of the crystal diameter and/or the crystal rotation rate increased the strength of the forced convection in the melt, and as a result, the temperature at the crystal growth interface increased. This resulted in a reduction of the crystal growth rate. On the other hand, the forced convection should be kept high enough to prevent floating particles attaching to the growing crystal. Therefore, in order to grow a larger single crystal, it was necessary to control the crystal rotation rate according to the change of the crystal diameter with time. We succeeded in crystal pulling along the c-axis of a relatively large Y123 single crystal which was 17 mm × 17 mm and 8 mm in length.

Characteristics of Oxygen Precipitation in Silicon Wafers Preannealed at 723K

1992 ◽  
Vol 262 ◽  
Author(s):  
I. Fusegawa ◽  
E. Iino ◽  
T. Hirohata ◽  
H. Yamagishi
Keyword(s):  
Crystal Growth ◽  
Thermal Treatment ◽  
Single Crystals ◽  
Single Step ◽  
Nonuniform Distribution ◽  
The Other ◽  
Growth Axis ◽  
Oxygen Precipitation ◽  
New Process ◽  
The One

ABSTRACTWe investigated phenomena of oxygen precipitation in silicon single crystals by two kinds of thermal treatment, supposing a CMOS fabrication process. The one consisted of the first annealing at 1123K for 4 hrs and the second annealing at 1423K for 16 hrs. The other one consisted of the annealing at 1273K for 4 hrs and the second annealing at 1423K for 13 hrs. In the results, a single-step preannealing at 723K for 2 hrs was effective for the oxygen precipitation by the former process and nonuniform distribution profiles along crystal growth axis were well improved, however, insufficiently improved against the latter process. We considered a two-step preannealing process consisting of the first annealing at 723K for 2 hrs and the second annealing at 923K for 2 hrs. This new process was effective for the oxygen precipitation by the latter process. Especially, we could obtain uniform distribution profiles of oxygen precipitation along a crystal growth axis.

Influence of Impurities in SiC Powder on High Quality SiC Crystal Growth

2016 ◽  
Vol 858 ◽  
pp. 85-88
Author(s):  
S. Heo ◽  
H.R. Son ◽  
Byung Sook Kim ◽  
M.S. Kim ◽  
J.E. Han ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Carbothermal Reduction ◽  
Impurity Content ◽  
The Other ◽  
High Quality ◽  
Other Hand ◽  
Traditional Process ◽  
Influence Of Impurities

SiC powders having different purities were prepared by carbothermal reduction under different conditions from traditional process and SiC single crystals were grown by the PVT method from the powders. After crystal growth, boule was cut to wafers and they were polished for chemical and defect analyses. Total impurities including Al, B and Ti which were derived from powders decreased remarkably during crystal growth. The formation of defects including micropipe and dislocations such as TED, TSD and BPD was strongly influenced by impurity content. The effect of impurity seemed to be negligible at below 1ppm level for MPD. On the other hand, dislocations continuously decreased even more when higher purity SiC powder below 1ppm level was used.

CeNi1-xSb1+yBi1-y Phases with ZrCuSiAs-type and CeNi1.26Sb2 with CaBe2Ge2-type Structure

2014 ◽  
Vol 69 (4) ◽  
pp. 409-416 ◽  
Author(s):  
Konrad Schäfer ◽  
Birgit Gerke ◽  
Oliver Niehaus ◽  
Rainer Pöttgen
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Solid Solutions ◽  
Small Difference ◽  
Magnetic Ordering ◽  
X Ray Diffraction ◽  
X Ray ◽  
By Products ◽  
Experimental Magnetic Moment ◽  
Growth Experiments

Block- and platelet-shaped single crystals of several CeNi1-xSb1+yBi1-y phases with ZrCuSiAstype structure (space group P4=nmm) were grown from a CeNiSb precursor in bismuth fluxes. The structures of CeNiSb1.19Bi0.81, CeNi0.80Sb1.16Bi0.84 and CeNi0.75Sb1.74Bi0.26 were refined from single-crystal X-ray diffractometer data. The 2b nickel site can be fully or partially occupied, and the bismuth square nets show solid solutions with antimony. CaBe2Ge2-type CeNi2-xSb2 crystals occur as by-products of the crystal growth experiments. The structure of a CeNi1.26Sb2 crystal has been refined. The small difference of the compositions hamper phase analytical studies by powder X-ray diffraction. A polycrystalline CeNiSbBi sample showed Curie-Weiss behavior with an experimental magnetic moment of 2.56(1) μB per Ce atom, indicating purely trivalent cerium. No magnetic ordering is detected down to 2:5 K. A 121Sb Mössbauer spectrum showed an isomer shift of δ = -8.06(6)mms-1, substantiating the antimonide character.

Seeded Crystal Growth of Yba2Cu3O6.5 in Semisolid Melts

1997 ◽  
Vol 12 (4) ◽  
pp. 880-890 ◽  
Author(s):  
S. Honjo ◽  
M. J. Cima ◽  
M. C. Flemings ◽  
T. Ohkuma ◽  
H. Shen ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystals ◽  
Particle Concentration ◽  
Volume Fraction ◽  
Isothermal Solidification ◽  
The Other ◽  
Oxide Content ◽  
Particle Segregation ◽  
Crystal Interface

Melt textured single crystals of YBa2Cu3O6.5 (123) superconductors were produced by isothermal solidification from a semisolid melt using single crystal NdBa2Cu3O6.5 or SmBa2Cu3O6.5 seeds. The microstructure within the single crystals shows an inhomogeneous segregation of Y2BaCO5 (211) particles trapped in the 123 crystals during solidification. The concentration of 211 particles varies with the crystal axes in 123 crystals produced from precursors with compositions of 80 wt.% 123 powder and 20 wt.% excess 211. The 211 particle concentration along the c-axis in the crystal is much lower than that along the a- or b-axes during initial crystallization. This concentration increases in both directions as the crystal grows larger. The 211 concentration along the c-axis increases more quickly than the concentration along the other axes during solidification, which allows the 211 concentration to approach that on the other axes as the solidification continues. 211 particle segregation in stoichiometric 123 samples formed “X”-shaped tracks instead of the variations in 211 concentration described above. A single crystal growth model of 123 is proposed and employed to interpret these experimental observations. Quenched samples were prepared to investigate the volume fraction of 211 particles in the liquid phase. A constant distribution of 211 particles was observed in the liquid, except very near the crystal interface, where the 211 concentration decreased rapidly. Copper oxide content in the liquid was also measured. It is found that the copper content is lower at the (001) interface compared with (100) or (010) interfaces.

Crystal growth and scintillation properties of tube shape-controlled Ce-doped Y3Al5O12 single crystals grown by micro-pulling-down method

2020 ◽  
Vol 13 (12) ◽  
pp. 125503
Author(s):  
Atsushi Kotaki ◽  
Masao Yoshino ◽  
Yuui Yokota ◽  
Takashi Hanada ◽  
Akihiro Yamaji ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Tube Shape ◽  
Shape Controlled

scholarly journals Single Crystal Growth and Physical Properties of Pyroxene CoGeO3

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 378
Author(s):  
Li Zhao ◽  
Zhiwei Hu ◽  
Hanjie Guo ◽  
Christoph Geibel ◽  
Hong-Ji Lin ◽  
...  
Keyword(s):  
High Pressure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Crystal Growth ◽  
Physical Properties ◽  
Single Crystal ◽  
Single Crystals ◽  
Magnetic Moments ◽  
Single Crystal Growth ◽  
The Impact

We report on the synthesis and physical properties of cm-sized CoGeO3 single crystals grown in a high pressure mirror furnace at pressures of 80 bar. Direction dependent magnetic susceptibility measurements on our single crystals reveal highly anisotropic magnetic properties that we attribute to the impact of strong single ion anisotropy appearing in this system with TN∼33.5 K. Furthermore, we observe effective magnetic moments that are exceeding the spin only values of the Co ions, which reveals the presence of sizable orbital moments in CoGeO3.

Trends in Rare Earth Thiophosphate Syntheses: Rb3Ln(PS4)2 (Ln = La, Pr, Ce), Rb3-xNaxLn(PS4)2 (Ln = Pr, Ce; x = 0.50, 0.55), and RbEuPS4 Obtained by Molten Flux Crystal Growth

CrystEngComm ◽  
2021 ◽  
Author(s):  
Logan S Breton ◽  
Mark D. Smith ◽  
Hans-Conrad Zur Loye
Keyword(s):  
Rare Earth ◽  
Crystal Growth ◽  
Single Crystals ◽  
Molten Flux

Single crystals of new rubidium rare earth thiophosphates with the formulas Rb3Ln(PS4)2 (Ln = La, Pr, Ce), Rb3-xNaxLn(PS4)2 (Ln = Pr, Ce; x = 0.50, 0.55), and RbEuPS4 were crystallized...

scholarly journals Numerical Analysis of Difficulties of Growing Large-Size Bulk β-Ga2O3 Single Crystals with the Czochralski Method

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Xia Tang ◽  
Botao Liu ◽  
Yue Yu ◽  
Sheng Liu ◽  
Bing Gao
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Czochralski Method ◽  
Liquid Interface ◽  
Spiral Growth ◽  
Growth Time ◽  
Large Size ◽  
Crystal Diameter ◽  
Solid Liquid Interface ◽  
Solid Liquid

The difficulties in growing large-size bulk β-Ga2O3 single crystals with the Czochralski method were numerically analyzed. The flow and temperature fields for crystals that were four and six inches in diameter were studied. When the crystal diameter is large and the crucible space becomes small, the flow field near the crystal edge becomes poorly controlled, which results in an unreasonable temperature field, which makes the interface velocity very sensitive to the phase boundary shape. The effect of seed rotation with increasing crystal diameter was also studied. With the increase in crystal diameter, the effect of seed rotation causes more uneven temperature distribution. The difficulty of growing large-size bulk β-Ga2O3 single crystals with the Czochralski method is caused by spiral growth. By using dynamic mesh technology to update the crystal growth interface, the calculation results show that the solid–liquid interface of the four-inch crystal is slightly convex and the center is slightly concave. With the increase of crystal growth time, the symmetry of cylindrical crystal will be broken, which will lead to spiral growth. The numerical results of the six-inch crystal show that the whole solid–liquid interface is concave and unstable, which is not conducive to crystal growth.

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