Differential Scanning Calorimetry and Guinier Camera/High-Temperature X-Ray Diffraction Studies of the Oxygen Sublattice Phase Transition in the Yba2Cu3O7−x System
| Autor: | William L. Johnson, Paul Pietrokowsky, Zezhong Fu, David S. Lee, Konrad Samwer, Egon Hellstern |
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| Rok vydání: | 1987 |
| Předmět: |
010302 applied physics
Phase transition Materials science Analytical chemistry chemistry.chemical_element 02 engineering and technology Partial pressure Activation energy 021001 nanoscience & nanotechnology 01 natural sciences Oxygen Differential scanning calorimetry chemistry 0103 physical sciences X-ray crystallography Limiting oxygen concentration 0210 nano-technology Electron backscatter diffraction |
| Zdroj: | MRS Proceedings. 99 |
| ISSN: | 1946-4274 0272-9172 |
| DOI: | 10.1557/proc-99-923 |
| Popis: | We have studied the phase transition of the oxygen sublattice in the YBa2Cu3O7−x system by Differential Scanning Calorimetry (DSC), Guinier Camera, and high temperature x-ray diffraction (ht-xrd) techniques. The transition was examined under different thermodynamic constraints (constant oxygen partial pressure and constant oxygen concentration) and for a range of oxygen partial pressures. The variation of the endothermic peak temperature with DSC scanning rate was used to deduce an activation energy for the transition. The average activation energy for the process is between 38.7–75.0 kcal/mole(l:2:3) [mole], depending on the thermodynamic constraint imposed on the system.Pressure versus concentration isotherms (P(C)) were used to determine the chemical potential of the oxygen in this system. |
| Databáze: | OpenAIRE |
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