First X-Ray Diffraction Evidence for a Phase Transition during Shock-Wave Compression

1972 ◽  
Vol 29 (20) ◽  
pp. 1369-1371 ◽  
Author(s):  
Quintin Johnson ◽  
A C. Mitchell
1978 ◽  
Vol 33 (8) ◽  
pp. 918-923 ◽  
Author(s):  
F. Müller ◽  
E. Schulte

Flash-x-ray-diffraction patterns (FXD) with an exposure time of 4 ns of NaCl single crystals compressed by plane shock waves are obtained at pressures of about 30 kbar. From the diffraction patterns the compression is determined and compared with Hugoniot data. During shock load the lattice shows an uniaxial compression. While in case of measurements at the free surface an observation time of only a few nanoseconds is available, this experimental set-up allows an observation time of two microseconds.


1970 ◽  
Vol 25 (16) ◽  
pp. 1099-1101 ◽  
Author(s):  
Quintin Johnson ◽  
A. Mitchell ◽  
R. Norris Keeler ◽  
L. Evans

1972 ◽  
Vol 16 ◽  
pp. 242-250
Author(s):  
A. C. Mitchell ◽  
Quintin Johnson ◽  
L. Evans

AbstractAs a result of interest stemming from shock wave studies carried out at Lawrence Livermore Laboratory, we have developed a capability to conduct x-ray diffraction studies in submicrosecond time intervals. This involves the use of a low impedance flash x-ray device. While there are many applications to which these techniques can be put, our first experiments deal with samples undergoing shock wave compression. These particular experiments are conducted by synchronizing a 40 to 50 nsec flash x-ray device to a shock front which is produced by the detonation of a high explosive placed in contact with a sample. Diffracted radiation is usually recorded on very sensitive film protected by a blast cassette. Thus far we have subjected lithium fluoride, aluminum, and carbon to pressures in the range of 100 to 300 kbar. Either powder or single crystal samples can be used. The principal difficulties of this experiment are the lack of sufficient intensity and the synchronization of the x-ray pulse to the shock front.


1972 ◽  
Vol 21 (1) ◽  
pp. 29-30 ◽  
Author(s):  
Quintin Johnson ◽  
Arthur C. Mitchell ◽  
L. Evans

Science ◽  
1967 ◽  
Vol 155 (3768) ◽  
pp. 1401-1404 ◽  
Author(s):  
R. G. Mcqueen ◽  
J. C. Jamieson ◽  
S. P. Marsh

1997 ◽  
pp. 161-169 ◽  
Author(s):  
M. B. Guseva ◽  
V. G. Babaev ◽  
V. M. Babina ◽  
V. V. Khvostov ◽  
A. Z. Zhuk ◽  
...  

2003 ◽  
Vol 82 (8) ◽  
pp. 1248-1250 ◽  
Author(s):  
Sergey I. Shkuratov ◽  
Evgueni F. Talantsev ◽  
James C. Dickens ◽  
Magne Kristiansen ◽  
Jason Baird

Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.


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