Characterization of nitrogen doped chemical vapor deposited single crystal diamond before and after high pressure, high temperature annealing

2004 ◽  
Vol 201 (11) ◽  
pp. 2473-2485 ◽  
Author(s):  
S. J. Charles ◽  
J. E. Butler ◽  
B. N. Feygelson ◽  
M. E. Newton ◽  
D. L. Carroll ◽  
...  
1997 ◽  
Vol 499 ◽  
Author(s):  
Andrew Israel ◽  
Yogesh K. Vohra

ABSTRACTGem quality diamond crystals are employed as anvils in high-pressure diamond cell research. Homoepitaxial growth experiments by microwave plasma-assisted chemical vapor deposition (MPCVD) have produced 1.76 mm (diameter) by 0.65 mm (thickness) sized diamonds. We report fundamental studies on diamond growth rate and quality as a function of reactor pressure and methane concentration, in a hydrogen plasma. By varying the growth conditions, large, single crystal diamond can be produced, which is ideal for manufacturing high pressure anvils.Traditional high pressure, high temperature (HPHT) techniques for production of synthetic diamond anvils are extremely expensive and chemical vapor deposition (CVD) provides an economically viable alternative. We report diamond growth rates up to 0.32 mg/hr, which are comparable to HPHT growth rates, and crystal quality approaching that of gem diamond. When perfected, diamond anvils produced from chemical vapor deposition methods could replace those manufactured by high pressure, high temperature synthesis.


Author(s):  
Gunter Heymann ◽  
Elisabeth Selb ◽  
Toni Buttlar ◽  
Oliver Janka ◽  
Martina Tribus ◽  
...  

By high-pressure/high-temperature multianvil synthesis a new high-pressure (HP) phase of Co3TeO6 was obtained. The compound crystallizes in the acentric trigonal crystal system of the Ni3TeO6-type structure with space group R3...


2020 ◽  
Vol 75 (6-7) ◽  
pp. 597-603
Author(s):  
Birgit Fuchs ◽  
Hubert Huppertz

AbstractThe non-centrosymmetric scandium borate ScB6O9(OH)3 was obtained through a high-pressure/high-temperature experiment at 6 GPa and 1473 K. Single-crystal X-ray diffraction revealed that the structure is isotypic to InB6O9(OH)3 containing borate triple layers separated by scandium layers. The compound crystallizes in the space group Fdd2 with the lattice parameters a = 38.935(4), b = 4.4136(4), and c = 7.6342(6) Å. Powder X-ray diffraction and vibrational spectroscopy were used to further characterize the compound and verify the proposed structure solution.


2020 ◽  
Vol 59 (6) ◽  
pp. 3579-3584
Author(s):  
Sun Woo Kim ◽  
Xiaoyan Tan ◽  
Corey E. Frank ◽  
Zheng Deng ◽  
Huaiyu Wang ◽  
...  

2020 ◽  
Vol 10 (9) ◽  
pp. 3329
Author(s):  
Konstantin G. Mikheev ◽  
Tatyana N. Mogileva ◽  
Arseniy E. Fateev ◽  
Nicholas A. Nunn ◽  
Olga A. Shenderova ◽  
...  

Laser-induced graphitization of 100 nm monocrystals of diamond particles synthesized by high-pressure high-temperature (HP-HT) methods is not typically observed. The current study demonstrates the graphitization of 150 nm HP-HT nanodiamond particles in ca. 20-μm-thick thin films formed on a glass substrate when the intensity of a focused 633 nm He-Ne laser exceeds a threshold of ~ 33 kW/cm2. Graphitization is accompanied by green luminescence. The structure and morphology of the samples were investigated before and after laser excitation while using X-ray diffraction (XRD), Raman spectroscopy, atomic force (AFM), and scanning electron microscopy (SEM). These observations are explained by photoionization of [Ni-N]- and [N]-centers, leading to the excitation of electrons to the conduction band of the HP-HT nanodiamond films and an increase of the local temperature of the sample, causing the transformation of sp3 HP-HT nanodiamonds to sp2-carbon.


2009 ◽  
Vol 29 (2) ◽  
pp. 317-324 ◽  
Author(s):  
Chang-Sheng Zha ◽  
Szczesny Krasnicki ◽  
Yu-Fei Meng ◽  
Chih-Shiue Yan ◽  
Joseph Lai ◽  
...  

2006 ◽  
Vol 47 ◽  
pp. 31-36
Author(s):  
Alberto Ubaldini ◽  
V.P.S. Awana ◽  
S. Balamurugan ◽  
E. Takayama-Muromachi

The ruthenocuprates family is a very interesting class of materials, because of the coexistence of superconductivity and magnetic ordering. Ruthenocuprates include RuSr2RECu2O8 and RuSr2(RE,Ce)2Cu2O10- (RE = rare earth elements or Y). It is possible to synthesize samples of these phases with Gd, Eu or Sm with normal synthesis conditions. For the others high-pressure high-temperature (HPHT) synthesis is required. We had successfully synthesized the RuSr2Tb1.5Ce0.5Cu2O10 by HPHT technique, starting from RuO2, SrO2, Tb4O7, CeO2, CuO and Cu. Around 300 mg of the mixture was allowed to react in a flat-belt-typehigh- pressure apparatus at 6GPa and 1200 °C – 1550 °C. The optimised temperature of synthesis was found to be in the range between 1350 °C – 1450 °C. The as-synthesized compound crystallized with a structure belonging to the space group I4/mmm. DC magnetic susceptibility versus temperature plot for RuSr2Tb1.5Ce0.5Cu2O10 in an applied field of 10 Oe demonstrated magnetic transition at 150 K but the superconducting transition was not clearly observed. To our knowledge this is the first successful synthesis of the Tb based Ru-1222 phase.


2017 ◽  
Vol 72 (12) ◽  
pp. 967-975 ◽  
Author(s):  
Martin K. Schmitt ◽  
Hubert Huppertz

AbstractNi6B22O39·H2O was synthesized in a high-pressure/high-temperature reaction at 5 GPa/900°C. It crystallizes in the orthorhombic space group Pmn21 (no. 31) with the lattice parameters a=7.664(2), b=8.121(2) and c=17.402(2) Å. The crystal structure is discussed with regard to the isotypic compounds M6B22O39·H2O (M=Fe, Co) and the structurally related phase Cd6B22O39·H2O. Furthermore, the characterization of Ni6B22O39·H2O via X-ray powder diffraction and vibrational spectroscopy is reported.


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