Effect of high‐energy mechanical milling on the medium‐range ordering in glassy As‐Se

Abstract

AbstractEffect of high‐energy mechanical milling on glassy AsxSe100 − x (5 ≤ x ≤ 75) is recognized with X‐ray powder diffraction analysis applied to their diffuse halos ascribed to intermediate—and extended‐range structural ordering, which are revealed respectively in the first sharp diffraction peak (FSDP) and principal diffraction peak (PDP). Straightforward interpretation of the results is developed within modified microcrystalline approach, treating diffuse halos as superposition of broadened Bragg‐diffraction reflexes from remnants of inter‐planar correlations, supplemented by inter‐atomic Ehrenfest‐diffraction reflexes from most prominent inter‐atomic and inter‐molecular correlations between cage‐like molecules (such As4Se4 and/or As4Se3). Milling is shown to be ineffective in glassy arsenoselenides near Se (x < 20), while causing increase in the FSDP width for glasses with 20 ≤ x ≤ 40 due to destroyed inter‐planar ordering. Remnants of cage‐like molecules in over‐stoichiometric As‐rich AsxSe100 − x glasses (40 ≤ x ≤ 75) disappear under milling, promoting formation of higher polymerized structural network. This milling‐driven reamorphization results in a drastic increase in the FSDP position and fragmentation impact on the correlation length of the FSDP‐responsible entities. Breakdown in intermediate‐range ordering in these glasses is accompanied by changes in their extended‐range ordering revealed in high‐angular shift and broadening of the PDP. This effect is concomitant with the disappearance of distant inter‐atomic correlations between quasi‐crystalline planes in the milled arsenoselenide glasses at a cost of prolonged correlations dominating in their extended‐range ordering.