

| 論文題目 | Pressure-Driven Cation Redistribution and Structural Evolution in Inverse Spinel NiAl2O4 |
| 論文題目(英文) | Pressure-Driven Cation Redistribution and Structural Evolution in Inverse Spinel NiAl2O4 |
| 作者 | 鄭直(1);熊夢君(1);梅升華(1) |
| 發(fā)表年度 | 2026-04-18 |
| 卷 | 26 |
| 期 | |
| 頁碼 | 9 |
| 期刊名稱 | CRYSTAL GROWTH & DESIGN |
| 摘要 |
Cation inversion in inverse spinel NiAl2O4 couples local coordination to macroscopic compressibility, yet its pressure evolution remains poorly constrained. Here, we quantify the inversion parameter i and oxygen positional parameter u by in situ X-ray diffraction in a diamond anvil cell. Rietveld refinements show that i increases from 0.753 at ambient pressure to 0.917 at 9.06 GPa, accompanied by a decrease of u over the same hydrostatic range. The unit-cell volume is well described by the equation of state fitted below similar to 10 GPa, yielding V 0 = 514.7(7)& Aring;3, B 0 = 238.53(15) GPa, and B 0 ' = 5.31(14). The average tetrahedral A-O bond length decreases overall with pressure, whereas the octahedral B-O bond length changes only modestly. The normalized average tetrahedral polyhedral volume decreases systematically, while the normalized octahedral polyhedral volume remains close to its ambient-pressure value within uncertainty. These results indicate that pressure-driven densification in NiAl2O4 involves coupled evolution of lattice compression, oxygen-framework relaxation, and cation redistribution, with a stronger relative response of the tetrahedral coordination environment over the investigated hydrostatic range. |
| 摘要_英文 |

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