Incommensurate phases in barium sodium niobate: Transmission-electron-microscopy study

Journal Article · Tue Nov 01 00:00:00 EST 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.38.9113· OSTI ID:6749957

Barre, S; Mutka, H; Roucau, C

A transmission-electron-microscopy study of barium sodium niobate has confirmed new features of the incommensurate phase. We present here images showing the nucleation of the incommensurate phase when the temperature increases after thermal cycling the sample or annealing in the incommensurate phase. In agreement with previous inferences, in situ annealing either at 230 /sup 0/C near the lock-in transition or at 270 /sup 0/C close to the tetragonal normal phase transition can favor the stability of a unidirectional 1q or a doubly modulated 2q incommensurate phase, respectively. The difference in the orientation of discommensurations, either perpendicular to the orthorhombic a axis or perpendicular to the tetragonal a and b axes, agree with an assignment of the two phases based on theoretical arguments and on x-ray and optical data.

• Research Organization: Laboratoire d'Optique Electronique du Centre National de la Recherche Scientifique, Boite Postale 4347, 31055 Toulouse Cedex, France
• OSTI ID: 6749957
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 38:13
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
NIOBATES
PHASE STUDIES
TRANSMISSION ELECTRON MICROSCOPY
ANNEALING
DOMAIN STRUCTURE
HYSTERESIS
MONOCRYSTALS
NUCLEATION
SAMPLE PREPARATION
ALKALINE EARTH METAL COMPOUNDS
CRYSTALS
ELECTRON MICROSCOPY
HEAT TREATMENTS
MICROSCOPY
NIOBIUM COMPOUNDS
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360102* - Metals & Alloys- Structure & Phase Studies