Origin of “memory glass” effect in pressure-amorphized rare-earth molybdate single crystals

Abstract

The memory glass effect (MGE) describes the ability of some materials to recover the initial structure and crystallographic orientation after pressure-induced amorphization (PIA). In spite of numerous studies the nature and underlying mechanisms of this phenomenon are still not clear. Here we report investigations of MGE in β′-Eu₂(MoO₄)₃ single crystal samples subjected to high pressure amorphization. Using the XRD and TEM techniques we carried out detailed analysis of the structural state of high pressure treated single crystal samples as well as structural transformations due to subsequent annealing at atmospheric pressure. The structure of the sample has been found to be complex, mainly amorphous, however, the amorphous medium contains evenly distributed nanosize inclusions of a paracrystalline phase. The inclusions are highly correlated in orientation and act as “memory units” in the MGE

Optimizing the synthesis of terbium(III) molybdate nanoplates through an orthogonal array design

“…Molybdate salts of rare‐earth elements have been used in phosphors, optical fibers, scintillators, laser hosts, and so forth. More specifically rare earth trimolybdates constitute an important class of compounds, which crystallize in different forms, that is, C2/c (α form), P421m (β form), Pba 2 (β form), and Pnca (γ form) as the monoclinic, tetragonal, orthorhombic, and cubic structures , while the (α) form is being thermodynamically stable for the rare‐earth salts of cations from Pr to the Ho. Upon cooling, the melt is converted to the metastable (β) form.…”