Domain structure in (La,Pr)GaO sub(3) solid solutions

• Published in: Ferroelectrics Vol. 254; no. 1-4; pp. 121 - 134
• Main Authors: Savytskii, D I, Vasylechko, L O, Berkowski, M, Fink-Finowicki, J, Aleksiyko, R, Byszewski, P, Matkovskii, A O
• Format: Journal Article
• Language: English
• Published: 01-01-2001
• ISSN: 0015-0193

Substitution of La by Pr in La sub(1-x)Pr sub(x)GaO sub(3) solids crystals leads to a decrease of spontaneous strains. There exist six possible twin states of the m3mFmmm species in the orthorthombic phase. The distorted perovskite unit cell becomes pseudotetragonal at composition x approximately 0.51 what leads to degeneracy to three twin states (the m3mF4/mmm species). The {110} and {112} reflection twins and axial twins with compositional planes close to {211} (S-walls) were identified in crystals with x=0.05, 0.10, 0.30. All observed twins are characteristic for crystals of GdFeO sub(3) type perovskite-like structure. It was shown that orientations of S-walls do not depend on La/Pr ratio in the ranges of x less than or equal to 0.3 and strongly vary in the composition range 0.3 < x < 0.8. A tilt angle between two twin states across twin boundary in La sub(1-x)Pr sub(x)GaO sub(3) is smaller than either in pure LaGaO sub(3) or PrGaO sub(3).