Raman spectroscopy at high pressure and high temperature. Phase transitions and thermodynamic properties of minerals

1996 ◽  
Vol 23 (4-5) ◽  
Author(s):  
P. Gillet
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Phase Transitions ◽  
High Temperature ◽  
Thermodynamic Properties ◽  
High Temperature Phase ◽  
Temperature Phase

scholarly journals High-Pressure and High-Temperature Phase Transitions in Fe2TiO4 and Mg2TiO4 with Implications for Titanomagnetite Inclusions in Superdeep Diamonds

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 614 ◽  
Author(s):  
Akaogi ◽  
Tajima ◽  
Okano ◽  
Kojitani
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Temperature ◽  
Spin Transition ◽  
Calcium Titanate ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Spinel Type ◽  
Perovskite Type

Phase transitions of Mg2TiO4 and Fe2TiO4 were examined up to 28 GPa and 1600 °C using a multianvil apparatus. The quenched samples were examined by powder X-ray diffraction. With increasing pressure at high temperature, spinel-type Mg2TiO4 decomposes into MgO and ilmenite-type MgTiO3 which further transforms to perovskite-type MgTiO3. At 21 GPa, the assemblage of MgTiO3 perovskite + MgO changes to 2MgO + TiO2 with baddeleyite (or orthorhombic I)-type structure. Fe2TiO4 undergoes transitions similar to Mg2TiO4 with pressure: spinel-type Fe2TiO4 dissociates into FeO and ilmenite-type FeTiO3 which transforms to perovskite-type FeTiO3. Both of MgTiO3 and FeTiO3 perovskites change to LiNbO3-type phases on release of pressure. In Fe2TiO4, however, perovskite-type FeTiO3 and FeO combine into calcium titanate-type Fe2TiO4 at 15 GPa. The formation of calcium titanate-type Fe2TiO4 at high pressure may be explained by effects of crystal field stabilization and high spin–low spin transition in Fe2+ in the octahedral sites of calcium titanate-type Fe2TiO4. It is inferred from the determined phase relations that some of Fe2TiO4-rich titanomagnetite inclusions in diamonds recently found in São Luiz, Juina, Brazil, may be originally calcium titanate-type Fe2TiO4 at pressure above 15 GPa in the transition zone or lower mantle and transformed to spinel-type in the upper mantle conditions.

High pressure and high temperature phase transitions of FeO

2004 ◽  
Vol 146 (1-2) ◽  
pp. 273-282 ◽  
Author(s):  
Motohiko Murakami ◽  
Kei Hirose ◽  
Shigeaki Ono ◽  
Taku Tsuchiya ◽  
Maiko Isshiki ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Temperature ◽  
High Temperature Phase ◽  
Temperature Phase

High-temperature phase transitions in CsH2PO4 under ambient and high-pressure conditions: A synchrotron x-ray diffraction study

2007 ◽  
Vol 127 (19) ◽  
pp. 194701 ◽  
Author(s):  
Cristian E. Botez ◽  
Juan D. Hermosillo ◽  
Jianzhong Zhang ◽  
Jiang Qian ◽  
Yusheng Zhao ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Temperature ◽  
Diffraction Study ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray

High temperature phase transitions and proton conductivity in some kdp-family crystals

1989 ◽  
Vol 100 (1) ◽  
pp. 135-141 ◽  
Author(s):  
A. I. Baranov ◽  
V. P. Khiznichenko ◽  
L. A. Shuvalov
Keyword(s):  
Phase Transitions ◽  
High Temperature ◽  
Proton Conductivity ◽  
High Temperature Phase ◽  
Temperature Phase

scholarly journals High-temperature phase transitions in dense germanium

2021 ◽  
Vol 154 (17) ◽  
pp. 174702
Author(s):  
Liam C. Kelsall ◽  
Miriam Peña-Alvarez ◽  
Miguel Martinez-Canales ◽  
Jack Binns ◽  
Chris J. Pickard ◽  
...  
Keyword(s):  
Phase Transitions ◽  
High Temperature ◽  
High Temperature Phase ◽  
Temperature Phase

High-temperature phase transitions in K3H(SO4)2

2001 ◽  
Vol 145 (1-4) ◽  
pp. 179-184 ◽  
Author(s):  
Calum R.I. Chisholm ◽  
Sossina M. Haile
Keyword(s):  
Phase Transitions ◽  
High Temperature ◽  
High Temperature Phase ◽  
Temperature Phase
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