Ferroelastic multidomains in LaNbO4 crystals

Abstract

LaNbO4 crystals show three lineal structures associated with domain formation under high-resolution polarizing optical microscope. One has a width of the order of 10 microns and the others are in order of 1 micron wide. The former is a large scale multidomain structure formed by twinning deformation due to monoclinic spontaneous strains below phase transition temperature and the latters are a small scale multidomain structure comming from discommensuration due to incommensurate-commensurate phase transition. Spacings of these multidomain structures are discussed on basis of experimental results and theoretical consideration.