Brazhkin, V. V.*; Katayama, Yoshinori; Kanzaki, Masami*; Kondrin, M. V.*; Lyapin, A. G.*
JETP Letters, 94(2), p.161 - 170, 2011/09
It is known that a number of compressed melts undergo structural phase transitions. Data on the structural changes at high pressures in chalcogenides (AsS, AsS) and oxide (BO) melts with a network structure have been reviewed. Viscosity is one of the fundamental physical properties of a liquid. For various melts, it varies in a very wide range. Structural transformations in melts induce the corresponding changes in all physical properties, in particular viscosity. The measurements of the viscosity of a number of melts at high pressures and temperatures by the radiographic method have been reported. Changes in the viscosity by several orders of magnitude have been detected when the pressure is varied by several gigapascals. The diffusion mechanism in network structure melts at various pressures has been analyzed.
Starikov, S. V.*; Stegailov, V. V.*; Norman, G. E.*; Fortov, V. E.*; Ishino, Masahiko; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Oba, Toshiyuki*; Kaihori, Takeshi; et al.
JETP Letters, 93(11), p.642 - 647, 2011/04
Brazhkin, V. V.*; Tsiok, O. B.*; Katayama, Yoshinori
JETP Letters, 89(5), p.244 - 248, 2009/05
Relative volume change of vitreous BO have been precisely measured by the strain-gauge technique at hydrostatic pressures up to 9 GPa. Smeared anomalies of compressibility (at P 0.5 GPa and P 5 GPa) and logarithmic relaxation of the glass density are observed. It has been revealed that there is a significant difference between the relaxed bulk modulus of glass obtained from the volume measurements and the unrelaxed modulus estimated from the Brillouin spectroscopic data. The basic features of the phase transitions in BO glass is revealed by the measurements of the relative volume change under compression together with the previous structure investigations and computer simulation results. Both direct and reverse transitions are smeared in pressure. The residual densification in glass is not associated with change in the short-range order.
Gasilov, S. V.*; Faenov, A. Y.; Pikuz, T. A.*; Skobelev, I. Yu.*; Calegari, F.*; Vozzi, C.*; Nisoli, M.*; Sansone, G.*; Valentini, G.*; De Silvestri, S.*; et al.
JETP Letters, 87(5), p.238 - 242, 2008/03
Faenov, A. Y.; Magunov, A. I.*; Pikuz, T. A.*; Skobelev, I. Y.*; Giulietti, D.*; Betti, S.*; Galimberti, M.*; Gamucci, A.*; Giulietti, A.*; Gizzi, L. A.*; et al.
JETP Letters, 86(3), p.178 - 183, 2007/08
Brazhkin, V. V.*; Katayama, Yoshinori; Lyapin, A. G.*; Popova, S. V.*; Inamura, Yasuhiro*; Saito, Hiroyuki; Utsumi, Wataru
JETP Letters, 82(11), p.713 - 718, 2005/12
The results of investigating the phase diagrams of ZnCl and AlCl halides, as well as the structure of the short range order of the corresponding melts under pressures up to 6.5 GPa, by the method of energy-dispersive X-ray diffraction are reported. When a ZnCl crystal is compressed, a phase transition occurs from the phase (HgI structure type) to the phase (distorted CdI structure, WTe type). The structural studies of the liquid state of ZnCl and AlCl indicate that the intermediate-range order decreases rapidly in the tetrahedral network of both melts as the pressure increases to 1.8 and 2.3 GPa for ZnCl and AlCl, respectively. With further compression, the transitions in both melts occur with a change in the structure of the short-range order and with an increase in the coordination number. In this case, the transition in AlCl occurs at about 4 GPa and is a sharp first order transition, whereas the transition in ZnCl occurs more smoothly in a pressure range of 2-4 GPa with a maximum intensity near 3 GPa. Thus the AlCl and ZnCl compounds exemplify the existence of two phenomena, gradual decay of intermidiate-range structural correlations and a sharper liquid-liquid coordination transition.
Fukuda, Yuji; Yamakawa, Koichi; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Abdallah, J. Jr.*; Csanak, G.*; Faenov, A. Y.*; Magunov, A. I.*; et al.
JETP Letters, 78(3), p.115 - 118, 2003/08
We have measured the X-ray emission spectra of a plasma generated by laser radiation with an intensity above 10 W/cm and a pulse duration of 30 fs acting uon an argon jet target with a large aboundance of micron-sized clusters. The time variation of the X-ray yeild from various multiplicities, calculated within the framework of a nonstationary kinetic model, shows a good qualitative agreement with the experimental time-integrated spectrum.
Brazhkin, V. V.*; Katayama, Yoshinori; Inamura, Yasuhiro; Kondrin, M. V.*; Lyapin, A. G.*; Popova, S. V.*; Voloshin, R. N.*
JETP Letters, 78(6), p.393 - 397, 2003/06
We present in situ (X-ray diffraction) and ex situ (quenching) structural studies of crystalline, liquid, and glassy BO up to 9 GPa and 1700 K, drawing equilibrium and nonequilibrium phase diagrams of BO, Particularly, we have determined the melting curve, the stability regions for crystalline BO and BO II modifications, the regions of transformations, such as densification or crystallization, for both the liquid and glassy states, including the region of sharp first-order-like transition in liquid BO to a high-density phase near 7 GPa. Quenching experiments also show that the transition to the high-density liquid can occur at much lower pressures in nonstoichiometric melts with an excess of boron. BO is the first glassformer whose transformations in the disordered state have been comparatively studied for both liquid and glassy phases.