Click here to view fulltext PDF

Permanent link:
https://www.ias.ac.in/article/fulltext/pram/043/01/0001-0009

Precursor phase transition; pressure-induced amorphization; α-GeO₂; α-AlPO₄; high pressure energy dispersive X-ray diffraction

Recent X-ray diffraction studies on α-quartz (SiO₂) by Kingmaet al [1], have shown the occurrence of a reversible, crystalline-to-crystalline, phase transition just prior to amorphization at ≈ 21 GPa. This precursor transition has also been confirmed by our recent molecular dynamics simulation study [2]. In order to investigate the possibility of a similar behaviour in other isostructural compounds, which also undergo pressure induced amorphization, α-GeO₂ and α-AlPO₄ (berlinite form) were studied using energy dispersive X-ray diffraction. In either of these materials, no such phase transition is detected prior to amorphization. The onset of amorphization and its reversal is found to be time dependent in GeO₂.

M S Somayazulu¹ Nandini Garg¹ Surinder M Sharma¹ S K Sikka¹

1. High Pressure Physics Division, Bhabha Atomic Research Centre, Bombay - 400 085, India

Published

July 1994

Manuscript received

25 April 1994