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

Journal Article · Tue Nov 01 04:00:00 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), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 38:13; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

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