Pressure induced amorphization of ZrMo2O8 and its relaxation on decompression as seen by in situ total x-ray scattering

Abstract

The pressure induced amorphization of the negative thermal expansion material cubic ZrMo2O8 was examined in situ within a diamond anvil cell, using high energy x-ray total scattering, during compression up to ∼7.2 GPa, and then decompressed. The amorphization upon compression was largely complete by ∼3 GPa. There was significant, but not complete, structural relaxation of the amorphous material on decompression; the pair distribution function (PDF) for the material recovered from 7.2 GPa closely resembled that for the sample during initial compression at ∼5.5 GPa. The PDFs indicated that the amorphization, densification, and relaxation of the amorphous solid involve changes in the first coordination shell of molybdenum and the creation/loss of Mo-O-M bridges with ∼3.4 Å Mo-M separation (M–Mo or Zr).

Zero Thermal Expansion and Abrupt Amorphization on Compression in Anion Excess ReO3-Type Cubic YbZrF7

“…We are not aware of any published work on related materials reporting abrupt amorphization on compression. While pressure-induced amorphization is common for negative thermal expansion framework materials, the loss of long-range structural order usually takes place over an extended pressure range. , The structural changes underpinning the abrupt amorphization are not clear and warrant further investigation.…”

Negative thermal expansion and associated anomalous physical properties: review of the lattice dynamics theoretical foundation

“…Several NTE materials are known to undergo pressureinduced amorphisation phase transitions, examples being ZrW 2 O 8 [264][265][266][267] and ZrMo 2 O 8 [238,268,269], Cu 2 O [252], NbOPO 4 [270] and Zn(CN) 2 [120]. Speedy [271] has suggested that NTE materials might be particularly susceptible to pressure-induced amorphisation.…”

Recent advances in the application of total scattering methods to functional materials

“…Pressure induced amorphization (PIA) is an interesting phenomenon which can be nicely investigated by means of total scattering methods. For example, studies by Wilkinson et al 62 and Lu et al 63 on ZrMo 2 O 8 and Ta 2 O 5 nanowires, respectively. Notably, these papers witness both the evolution of the sample environments available for PDF experiments and the great engineering and scientific work done in order to overcome all the problems strictly correlated to the narrow angular window due to the utilization of pressure cells.…”