Possible Species of “Ferroelastic” Crystals and of Simultaneously Ferroelectric and Ferroelastic Crystals

TLDR

Ferroelastic crystals are defined analogously to ferroelectric crystals, with mechanical strain and stress corresponding to electric polarization and field, and their coercive stress is typically on the order of 10² N·cm⁻². The study aims to enumerate all theoretically possible ferroelastic crystal species and to determine the number of states and whether each species is ferroelectric or not. The authors performed a theoretical analysis to identify all possible ferroelastic crystal species and assess their state counts and ferroelectric properties. The analysis revealed 94 ferroelastic species, of which 42 are simultaneously ferroelectric, and the authors updated the symbols for 88 ferroelectric species.

Abstract

It is convenient to grasp crystals of a kind as “ferroelastic” crystals. They are defined analogously to “ferroelectric” crystals, mechanical strain and stress in the former corresponding to electric polarization and field in the latter respectively. The order of magnitude of the coercive stress for ferroelastic state-shifts which corresponds to the coercive field for ferroelectric state-shifts is expected, on the average, to be 10 2 newt·cm -2 . A determination is made of all theoretically possible species of ferroelastic crystals and the number of states and ferroelectricity or nonferroelctricity in each of these species. It is found that there are 94 of these ferroelastic species and that 42 of them are simultaneously ferroelectric. Incidentally, an alteration is made of the hitherto used symbols for the 88 species of ferroeletric crystals.