scholarly journals Kristallstruktur von SrGe2 bei hohen Drücken / Crystal Structure of SrGe2 at High Pressures

1979 ◽  
Vol 34 (3) ◽  
pp. 524 ◽  
Author(s):  
Jürgen Evers ◽  
Gilbert Oehlinger ◽  
Armin Weiss
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
High Pressures ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Space Group ◽  
High Pressure High Temperature

Abstract After a high pressure -high temperature treatment of orthorhombic SrGe2 (BaSi2 type of structure) a trigonal polymorph (EuGe2 type of structure) is obtained: space group P3̄m 1; a - 410.4 pm, c - 516.5 pm; Z - 1; zGe = 0.406.

Preparation of CoGe2-type NiSn2 at 10 GPa

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Andreas Leineweber ◽  
Marius Holger Wetzel ◽  
Stefan Martin ◽  
Shun-Li Shang ◽  
Zi-Kui Liu
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Temperature Treatment ◽  
Group Symmetry ◽  
High Temperature Treatment ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
High Pressure High Temperature ◽  
Type Crystal

Abstract An unprecedented NiSn2 intermetallic with CoGe2-type crystal structure has been recovered (at ambient conditions) after high-pressure high-temperature treatment of a Ni33Sn67 precursor alloy at 10 GPa and 400 °C. The orthorhombic structure with Aeam space group symmetry is pseudotetragonal. Based on the evaluation of powder X-ray diffraction data, lattice parameters of a = b = 6.2818 Å and c = 11.8960 Å have been determined. Complicated line broadening and results of a further microstructure analysis, however, imply a defective character of the crystal structure. First-principles calculations with different model structures and a comparison with structural trends in the literature suggest that at the high-pressure high-temperature conditions a CuAl2-type crystal structure might be stable, which transforms to the recovered CoGe2-type crystal structure upon cooling or the release of pressure.

Phase transformations in solid C60 at high-pressure-high-temperature treatment and the structure of 3D polymerized fullerites

1996 ◽  
Vol 220 (1-3) ◽  
pp. 149-157 ◽  
Author(s):  
V.D. Blank ◽  
S.G. Buga ◽  
N.R. Serebryanaya ◽  
G.A. Dubitsky ◽  
S.N. Sulyanov ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Phase Transformations ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
High Pressure High Temperature

scholarly journals High-Pressure Synthesis, Crystal Structure, and Photoluminescence Properties of β-Y2B4O9:Eu3+

Inorganics ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 136
Author(s):  
Fuchs ◽  
Schröder ◽  
Heymann ◽  
Jüstel ◽  
Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Single Crystal ◽  
Photoluminescence Properties ◽  
Triclinic Space Group ◽  
Space Group ◽  
High Pressure High Temperature ◽  
Temperature Experiment ◽  
Pressure Synthesis

A high-pressure/high-temperature experiment at 7.5 GPa and 1673 K led to the formation of the new compound βY2B4O9. In contrast to the already known polymorph αY2B4O9, which crystallizes in the space group C2/c, the reported structure could be solved via single-crystal Xray diffraction in the triclinic space group P1 (no. 2) and is isotypic to the already known lanthanide borates βDy2B4O9 and βGd2B4O9. Furthermore, the photoluminescence of an europium doped sample of βY2B4O9:Eu3+ (8%) was investigated.

Synthesis, Structure and Dielectric Properties of Na2SnTeO6

1998 ◽  
Vol 547 ◽  
Author(s):  
J.-H. Park ◽  
P.M. Woodward ◽  
J.B. Parise ◽  
I. Lubomirsky ◽  
O. Stafsudd
Keyword(s):  
Dielectric Constant ◽  
High Pressure ◽  
High Temperature ◽  
Dielectric Properties ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Powder Diffraction Data ◽  
Ambient Conditions ◽  
X Ray ◽  
High Pressure High Temperature

AbstractA new perovskite was recovered from the high pressure-high temperature treatment of the α-TlSbO3 form of Na2SnTeO6 at 7 GPa and 950 °C for 30 minutes. Synchrotron x-ray powder diffraction data show the space group is P21/n with a=5.40361 (5), b=5.46152(5), c=7.69288(7) Å and ß=90.034(3)°. Using disk samples of both polymorphs, the dielectric properties were measured as a function of temperature. At ambient conditions, the perovskite form has a more than 1.5 fold enhancement in dielectric constant compared to the α-TlSbO3 form while the molar volume and the molecular polarizability decrease.

Superconductivity in SmFeAsO0.8F 0.2 Synthesized by High Pressure High Temperature Treatment

2011 ◽  
Vol 197-198 ◽  
pp. 499-502
Author(s):  
Zheng He Hua ◽  
Heng Zhang ◽  
Ju Peng
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Electrical Transport ◽  
Upper Critical Field ◽  
Magnetic Field Effect ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
X Ray Diffraction ◽  
High Pressure High Temperature ◽  
High Transition

Superconducting SmFeAsO0.8F0.2 compound was successfully synthesized by high pressure high temperature treatment with pressure of 6 G Pa at 1400 °C for 2 hours. The X-ray diffraction pattern of the sample indicates the formation of the tetragonal ZrCuSiAs-type SmFeAsO0.8F0.2 with lattice parameters a=3.932 Å and c=8.490 Å. The electrical transport study shows that the sample has a rather high transition temperature Tc of about 52 K, and magnetic field effect on the resistance reveals a rather high upper critical field HC2 of about 65 T.

Polymerization and phase diagram of solid C70 after high-pressure-high-temperature treatment

1998 ◽  
Vol 248 (5-6) ◽  
pp. 415-422 ◽  
Author(s):  
V.D. Blank ◽  
N.R. Serebryanaya ◽  
G.A. Dubitsky ◽  
S.G. Buga ◽  
V.N. Denisov ◽  
...  
Keyword(s):  
Phase Diagram ◽  
High Pressure ◽  
High Temperature ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
High Pressure High Temperature
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