Twin Structure of (La, Nd)GaO3 Solid Solutions

✍ Scribed by D.I. Savytskii; M. Berkowski; L.O. Vasylechko; J. Fink-Finowicki; A.O. Matkovskii

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 485 KB
• Volume: 35
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/(sici)1521-4079(200001)35:1<53::aid-crat53>3.0.co;2-m

✦ Synopsis

For La 1-x Nd x GaO 3 crystals the La-Nd substitution leads to decrease of spontaneous strains and for composition with x≈0.32 the six possible twin states of orthorhombic phase (m3mFmmm) may be degenerated in three twin states inhered in m3mF4/mmm species when a distorted perovskite pseudocell becomes tetragonal. The {110} and {112} reflection twins and axial twins with compositional planes close to (211) and ( ) (S-walls) were identified in La 1-x Nd x GaO 3 (x=0.07, 0.12, 0.20) solid solutions crystals. All observed twins are typical for crystals with GdFeO 3 type perovskitelike structure. It has been shown that for x≤0.2 and x≥0.5 orientations of S-walls weakly depend on La/Nd ratio, whereas in the range of 0.2<x<0.5 they depend strongly on the solid solution composition. The tilt angle between two twin states across twin boundary in La 1-x Nd x GaO 3 (x<0.6) solid solutions is smaller than that between two twins in pure LaGaO 3 or NdGaO 3 .