The importance of cation–cation repulsion in the zircon–reidite phase transition and radiation-damaged zircon

2019 ◽  
Vol 83 (4) ◽  
pp. 561-567
Author(s):  
Makoto Tokuda ◽  
Akira Yoshiasa ◽  
Hiroshi Kojitani ◽  
Saki Hashimoto ◽  
Seiichiro Uehara ◽  
...  
Keyword(s):  
Phase Transition ◽  
Single Crystals ◽  
Lattice Distortion ◽  
Thermal Recovery ◽  
Radioactive Elements ◽  
X Ray Diffraction ◽  
Natural Radiation ◽  
X Ray

AbstractSingle crystals of synthetic reidite and natural radiation-damaged zircon from Okueyama, Japan were investigated using X-ray diffraction. The pressure-induced zircon–reidite transition is described by the twisting and translations of SiO4 tetrahedra with disappearance of the SiO4–ZrO8 shared edges. The lattice of radiation-damaged zircons expands mainly from α-decays of radioactive elements such as U and Th. Although old radiation-damaged zircons show anomolous lattice distortion, young radiation-damaged zircons do not show such distortions. These distortions are caused by thermal recovery that suppresses the Si4+–Zr4+ repulsion between the SiO4 tetrahedron and ZrO8 dodecahedron. These changes in structure can be understood by considering the cation–cation repulsion between the SiO4–ZrO8 shared edges.

Structural-phase transition in (Cu2Te)2−x(ZnTe)x at high temperature

2021 ◽  
pp. 2150113
Author(s):  
H. B. Gasimov ◽  
R. M. Rzayev
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
High Temperature ◽  
Single Crystals ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Xrd Study ◽  
Xrd Method

Cu2Te single crystal was grown by the Bridgman method. X-ray diffraction (XRD) study of Cu2Te single crystals in the temperature range of 293–893 K was performed and possible phase transitions in the mentioned range of temperature have been investigated. (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals also were grown with [Formula: see text], 0.05, 0.10 concentrations and structural properties of the obtained single crystals were investigated by the XRD method in the temperature range 293–893 K. Lattice parameters and possible phase transitions in the mention temperature range were determined for (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals for [Formula: see text], 0.05, 0.10 concentrations.

scholarly journals Electronic and Crystallographic Examinations of the Homoepitaxially Grown Rubrene Single Crystals

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1978 ◽  
Author(s):  
Yasuo Nakayama ◽  
Masaki Iwashita ◽  
Mitsuru Kikuchi ◽  
Ryohei Tsuruta ◽  
Koki Yoshida ◽  
...  
Keyword(s):  
Single Crystals ◽  
Valence Band ◽  
Lattice Distortion ◽  
Grazing Incidence ◽  
Valence Band Maximum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Homoepitaxial Growth ◽  
Highly Sensitive ◽  
Doping Ratio

Homoepitaxial growth of organic semiconductor single crystals is a promising methodology toward the establishment of doping technology for organic opto-electronic applications. In this study, both electronic and crystallographic properties of homoepitaxially grown single crystals of rubrene were accurately examined. Undistorted lattice structures of homoepitaxial rubrene were confirmed by high-resolution analyses of grazing-incidence X-ray diffraction (GIXD) using synchrotron radiation. Upon bulk doping of acceptor molecules into the homoepitaxial single crystals of rubrene, highly sensitive photoelectron yield spectroscopy (PYS) measurements unveiled a transition of the electronic states, from induction of hole states at the valence band maximum at an adequate doping ratio (10 ppm), to disturbance of the valence band itself for excessive ratios (≥ 1000 ppm), probably due to the lattice distortion.

Brillouin scattering near the α–β phase transitions of N2 and CO

1988 ◽  
Vol 66 (4) ◽  
pp. 541-548 ◽  
Author(s):  
V. Askarpour ◽  
H. Klefte ◽  
M. J. Clouter
Keyword(s):  
Phase Transition ◽  
Single Crystals ◽  
Elastic Constants ◽  
Brillouin Scattering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Mode Softening ◽  
Cubic Structure

The technique of high resolution Brillouin spectroscopy has been used to determine the adiabatic elastic constants of single crystals of β-N2 and β-CO as a function of temperature, in an effort to study the α–β phase transition. For all elastic constants, there is an increase of approximately 1%/K on cooling and there is no evidence of further mode softening, even within 0.5 K of the phase transition. Three large single crystals of α-CO were grown. The orientations were determined, by Laue X-ray diffraction, and correlated to the orientations of the parent β-crystals. The β-phase hexagonal basal planes appear to transform to planes of the form {110} in the α-phase cubic structure.

CHARACTERIZATION OF KHCO3 SINGLE CRYSTALS

2004 ◽  
Vol 11 (01) ◽  
pp. 83-86 ◽  
Author(s):  
S. ABOUELHASSAN ◽  
F. SALMAN ◽  
M. ELMANSY ◽  
E. SHEHA
Keyword(s):  
Phase Transition ◽  
Activation Energy ◽  
Aqueous Solution ◽  
Single Crystals ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slow Evaporation Technique ◽  
Evaporation Technique

Single crystals of KHCO 3 were grown by the slow evaporation technique of an aqueous solution. Characterization of the sample was done using different techniques such as X-ray diffraction, infrared spectra (IR) and the differential scanning calorimeter (DSC) technique. The analysis of the X-ray diffraction pattern indicated that the sample was a single crystal. The results obtained by IR and DSC indicated the presence of phase transition. From the analysis of DSC, the activation energy of transition was carried out by two methods (Kissinger and Ozawa).

Orthorhombic lattice deformation of CuAlBe shape-memory single crystals under cyclic strain

2001 ◽  
Vol 34 (6) ◽  
pp. 722-729 ◽  
Author(s):  
A. Tidu ◽  
A. Eberhardt ◽  
B. Bolle ◽  
F. Moreau ◽  
J.-J. Heizmann
Keyword(s):  
Shape Memory ◽  
Single Crystals ◽  
Fatigue Test ◽  
Lattice Distortion ◽  
Cyclic Strain ◽  
Fatigue Behaviour ◽  
X Ray Diffraction ◽  
Strong Decrease ◽  
X Ray ◽  
Ray Methods

X-ray diffraction experiments were carried out to prove that X-ray methods can be used to assess strain-induced fatigue in CuAlBe shape-memory alloys. The pseudoelastic fatigue behaviour of CuAlBe single crystals presents a strong decrease of the critical stress of the martensitic transformation. During the fatigue test, the austenitic lattice exhibits a lattice distortion. This lattice distortion evolves during the fatigue test: the austenitic cubic lattice (β1) tends to transform gradually towards an orthorhombic one. Various hypotheses concerning this lattice distortion are proposed.

Growth and Ferroelectric/Piezoelectric Properties of (K,Na)(Nb,Ta)O3 Ferroelectric Single Crystals

2013 ◽  
Vol 566 ◽  
pp. 64-67 ◽  
Author(s):  
Takuya Hattori ◽  
Yuuki Kitanaka ◽  
Yuji Noguchi ◽  
Masaru Miyayama
Keyword(s):  
Phase Transition ◽  
Dielectric Properties ◽  
Single Crystals ◽  
Composition Range ◽  
Piezoelectric Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Oxygen Pressure ◽  
Top Seeded Solution Growth ◽  
Successive Phase

Single crystals of (K,Na)Nb1-xTaxO3(KNNT) were grown by the top-seeded solution growth (TSSG) method under high oxygen pressure atmosphere (Po2= 0.9 MPa), and their dielectric properties were investigated along [10cubic(the cubic notation). KNNT single crystals in a composition range of 0x0.65 were successfully obtained. Through the measurements of x-ray diffraction and dielectric properties, we propose a temperature (T)-composition (x) phase diagram in the KNNT system in which a successive phase transition from orthorhombic (Amm2), tetragonal (P4mm) to cubic (Pmm) occurs with increases inTandx.

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