Ultrafast X-Ray Diffraction Studies of the Phase Transitions and Equation of State of Scandium Shock Compressed to 82 GPa.

Using x-ray diffraction at the Linac Coherent Light Source x-ray free-electron laser, we have determined simultaneously and self-consistently the phase transitions and equation of state (EOS) of the lightest transition metal, scandium, under shock compression. On compression scandium undergoes a structural phase transition between 32 and 35 GPa to the same bcc structure seen at high temperatures at ambient pressures, and then a further transition at 46 GPa to the incommensurate host-guest polymorph found above 21 GPa in static compression at room temperature. Shock melting of the host-guest phase is observed between 53 and 72 GPa with the disappearance of Bragg scattering and the growth of a broad asymmetric diffraction peak from the high-density liquid.

[1]  D. Hayes.  Unsteady compression waves in interferometer windows , 2001 .

[2]  One-dimensional chain melting in incommensurate potassium , 2015, 1504.02895.

[3]  H. Mao,et al.  First-order liquid-liquid phase transition in cerium. , 2013, Physical review letters.

[4]  S. Sutton,et al.  Structure of liquid iron at pressures up to 58 GPa. , 2004, Physical review letters.

[5]  J. Forbes.  Shock Wave Compression of Condensed Matter , 2012 .

[6]  W. Gust,et al.  New electronic interactions in rare-earth metals at high pressure , 1973 .

[7]  D. Allan,et al.  SELF-HOSTING INCOMMENSURATE STRUCTURE OF BARIUM IV , 1999 .

[8]  Sébastien Boutet,et al.  The CSPAD megapixel x-ray camera at LCLS , 2012, Other Conferences.

[9]  Jon H. Eggert,et al.  Systematic uncertainties in shock-wave impedance-match analysis and the high-pressure equation of state of Al , 2005 .

[10]  M. McMahon,et al.  High-pressure structures and phase transformations in elemental metals. , 2006, Chemical Society reviews.

[11]  V. Fortov,et al.  Electrophysical and thermodynamic properties of shock compressed incommensurate phase Sc-II , 2007 .

[12]  Chris J Pickard,et al.  Aluminium at terapascal pressures. , 2010, Nature materials.

[13]  Margaret Nichols.  Trans , 2015, De-centering queer theory.

[14]  P. Kam,et al.  : 4 , 1898, You Can Cross the Massacre on Foot.

[15]  H. J. Lee,et al.  Ultrafast visualization of crystallization and grain growth in shock-compressed SiO2 , 2015, Nature Communications.

[16]  D. Turnbull,et al.  Ultrabright X-ray laser scattering for dynamic warm dense matter physics , 2015, Nature Photonics.

[17]  C. Hejny,et al.  Different incommensurate composite crystal structure for Sc-II , 2006 .

[18]  J. N. Fritz,et al.  Hugoniot equation of state of the lanthanides , 1975 .

[19]  H. J. Lee,et al.  Direct Observation of Melting in Shock-Compressed Bismuth With Femtosecond X-ray Diffraction. , 2015, Physical review letters.

[20]  David K. Bradley,et al.  Line-imaging velocimeter for shock diagnostics at the OMEGA laser facility , 2004 .

[21]  Doyle Geiselman.  The metallurgy of scandium , 1962 .

[22]  Neil W. Ashcroft,et al.  Structure and Resistivity of Liquid Metals , 1966 .

[23]  D. Kalantar,et al.  High-pressure nanocrystalline structure of a shock-compressed single crystal of iron , 2008 .

[24]  Antje Sommer,et al.  Theory Of Simple Liquids , 2016 .

[25]  Ted Taylor.  Los Alamos National Laboratory , 2005 .

[26]  M. McMahon,et al.  Incommensurate crystal structures in the elements at high pressure , 2004 .

[27]  M. Mezouar,et al.  High melting points of tantalum in a laser-heated diamond anvil cell. , 2010, Physical review letters.

[28]  M. McMahon,et al.  Chain "melting" in the composite Rb-IV structure. , 2004, Physical review letters.

[29]  Y. Akahama,et al.  New helical chain structure for scandium at 240 GPa. , 2005, Physical review letters.

[30]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[31]  S. Takeya,et al.  Incommensurate composite crystal structure of scandium-II , 2005 .

[32]  B. Warren,et al.  The Effect of Cold‐Work Distortion on X‐Ray Patterns , 1950 .

[33]  Bob Nagler,et al.  The Matter in Extreme Conditions instrument at the Linac Coherent Light Source , 2015, Journal of synchrotron radiation.

[34]  G. Morard,et al.  Melting of Iron at Earth’s Inner Core Boundary Based on Fast X-ray Diffraction , 2013, Science.

[35]  A. P. Hammersley,et al.  Two-dimensional detector software: From real detector to idealised image or two-theta scan , 1996 .

[36]  L. M. Barker,et al.  Shock wave study of the α ⇄ ε phase transition in iron , 1974 .