Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate

Gallington, Leighanne C.; Hester, Brett R.; Kaplan, Benjamin S.; Wilkinson, Angus P.

doi:10.1016/j.jssc.2017.02.014

Cited by 11 publications

(5 citation statements)

References 57 publications

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“…This suggests that applications at increased temperatures may see a reversion to the orthorhombic structure under moderate pressures. Such temperature/pressure dependent phase transitions were observed for ZrV 2 O 7 (Gallington et al, 2017), which shows positive expansion in a 3 × 3 × 3 superstructure below 100 °C and NTE in a simple cubic cell at higher temperatures. Chapman and Chupas have estimated that NTE materials are likely to be subjected to pressures of ~1 GPa when used in composites (Chapman and Chupas, 2007).…”

Section: Resultssupporting

confidence: 52%

High Pressure Behavior of Chromium and Yttrium Molybdate (Cr2Mo3O12, Y2Mo3O12)

2018

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The high pressure behavior of negative thermal expansion materials continues to be of interest, as their potential use in controlled thermal expansion composites can be affected by irreversible pressure-induced phase transitions. To date, it is not possible to predict the high pressure behavior of these compounds, necessitating measurements on each composition. In this work, high pressure synchrotron powder X-ray diffraction studies of Cr2Mo3O12 and Y2Mo3O12 were conducted in a diamond anvil cell. Chromium molybdate, which adopts the monoclinic P21/a structure under ambient conditions, was found to not undergo any crystalline-crystalline transitions up to 8.9 GPa. The orthorhombic ambient pressure polymorph of yttrium molybdate was found to undergo a phase transition to the monoclinic P21/a scandium tungstate structure below 0.13 GPa. This structure is frequently observed for related materials at low temperatures, but has never been reported for Y2Mo3O12. No additional changes in this material were observed up to 4.9 GPa. The fact that the monoclinic polymorphs of these materials do not undergo phase transitions within the studied pressure range makes them unique among A2M3O12 materials, as most isostructural compositions undergo at least one phase transition to crystalline high pressure phases.

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Section: Resultssupporting

confidence: 52%

High Pressure Behavior of Chromium and Yttrium Molybdate (Cr2Mo3O12, Y2Mo3O12)

2018

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“…This behavior was experimentally confirmed, for example, in zinc cyanide [4]. However, a few years ago, it was discovered that pressure induces switching between thermal contraction and expansion in ferroelectric PbTiO 3 [5], and similar reverse behavior was observed in other compounds [6][7][8].…”

mentioning

confidence: 67%

On the switching between negative and positive thermal expansion in framework materials

Sanson

2019

Materials Research Letters

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Thermal expansion is a problem in many technological applications and its control represents a challenge in materials design. In this Letter, after studying the correlation between thermal expansion, cubic-to-rhombohedral transition and lattice parameter of ReO 3 -type structures, I show how in the different methods for controlling thermal expansion the key element is actually the lattice parameter. By varying the lattice parameter through external pressure, chemical modifications or other methods, the single-well potential energy of the octahedral rotation, responsible for Negative Thermal Expansion (NTE), can be turned into a quartic anharmonic potential or into a doublewell potential, thus enhancing or suppressing the NTE, respectively. This result can be extended to other framework-structures and should be taken into account to overcome the challenge of controlling thermal expansion.PACS numbers:

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“…20 This theoretical behavior is sometimes observed, 21 sometimes not. [22][23][24] Chemical modification by intercalation can be used to control the thermal expansion, e.g. by reversible wetting in nanopores of MOFs, 25 adsorption of CO2 in a MOF structure to reach a zero expansion material, 26 or by polymerizing ethylene in the pores of silicalite, which changes the sign of the volumetric thermal expansion from negative to positive.…”

Section: Introductionmentioning

confidence: 99%