High-temperature and high-pressure study on columbite structured ZnNb2O6

Fuente: arXiv
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Autori principali: Tyagi, A., Botella, P., Garg, A. B., Sanchez-Martin, J., Diaz-Anichtchenko, D., Turnbull, R., Anzellini, S., Popescu, C., Errandonea, D.
Natura: Preprint
Pubblicazione: 2025
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author Tyagi, A.
Botella, P.
Garg, A. B.
Sanchez-Martin, J.
Diaz-Anichtchenko, D.
Turnbull, R.
Anzellini, S.
Popescu, C.
Errandonea, D.
author_facet Tyagi, A.
Botella, P.
Garg, A. B.
Sanchez-Martin, J.
Diaz-Anichtchenko, D.
Turnbull, R.
Anzellini, S.
Popescu, C.
Errandonea, D.
contents High-temperature and high-pressure experiments were conducted on columbite-type ZnNb2O6, reaching temperatures up to 873 K at ambient pressure and pressures up to 30 GPa at ambient temperature, respectively. Through systematic analysis employing synchrotron powder X-ray diffraction and Raman spectroscopy, we examined the crystal structure and phonon behavior. Within the specified temperature range, the orthorhombic phase of ZnNb2O6 (space group: Pbcn) demonstrated notable phase stability, with a thermal expansion coefficient similar to that of isomorphic compounds. Notably, a reversible phase transition was observed under compression at 10 GPa, with diffraction experiments indicating a shift to a monoclinic structure (space group P2/a), which remained stable up to 30 GPa. Changes in Raman modes, lattice parameters, and the unit-cell volume were monitored. A significant 2.5% discontinuity in the unit-cell volume at the phase transition pressure from orthorhombic to monoclinic suggests a first-order phase transition. The bulk moduli of the orthorhombic and monoclinic phases were estimated as 165(7) GPa and 230(9) GPa, respectively- We also found that both phases exhibit an anisotropic response to pressure. Furthermore, first-principles calculations support consistently with experimental observations.
format Preprint
id arxiv_https___arxiv_org_abs_2508_03658
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle High-temperature and high-pressure study on columbite structured ZnNb2O6
Tyagi, A.
Botella, P.
Garg, A. B.
Sanchez-Martin, J.
Diaz-Anichtchenko, D.
Turnbull, R.
Anzellini, S.
Popescu, C.
Errandonea, D.
Materials Science
High-temperature and high-pressure experiments were conducted on columbite-type ZnNb2O6, reaching temperatures up to 873 K at ambient pressure and pressures up to 30 GPa at ambient temperature, respectively. Through systematic analysis employing synchrotron powder X-ray diffraction and Raman spectroscopy, we examined the crystal structure and phonon behavior. Within the specified temperature range, the orthorhombic phase of ZnNb2O6 (space group: Pbcn) demonstrated notable phase stability, with a thermal expansion coefficient similar to that of isomorphic compounds. Notably, a reversible phase transition was observed under compression at 10 GPa, with diffraction experiments indicating a shift to a monoclinic structure (space group P2/a), which remained stable up to 30 GPa. Changes in Raman modes, lattice parameters, and the unit-cell volume were monitored. A significant 2.5% discontinuity in the unit-cell volume at the phase transition pressure from orthorhombic to monoclinic suggests a first-order phase transition. The bulk moduli of the orthorhombic and monoclinic phases were estimated as 165(7) GPa and 230(9) GPa, respectively- We also found that both phases exhibit an anisotropic response to pressure. Furthermore, first-principles calculations support consistently with experimental observations.
title High-temperature and high-pressure study on columbite structured ZnNb2O6
topic Materials Science
url https://arxiv.org/abs/2508.03658