Evidence for a surface anomaly during the cubic-tetragonal phase transition in BaTiO 3 (001)

N. Barrett (1) , J. Dionot (1) , D. Martinotti (2) , E. Salje (3) , C. Mathieu (1)

1 LENSIS - Laboratoire d'Etude des NanoStructures et Imagerie de Surface
2 LEPO - Laboratoire d'Electronique et nanoPhotonique Organique
3 CAM - University of Cambridge [UK]

We have used low energy electron microscopy (LEEM) to study the evolution of the surface structure of BaTiO3(001) during the ferroelectric-paraelectric phase transition (120 °C, P4mm-Pm3m). Transient surface structures appear under heating at temperatures slightly above TC. Intersections between polar domain walls and the sample surface persist in the surface layer at 126.0 °C while the bulk has already transformed into the cubic phase. The wall signals are criss-crossed by a second set of stripe patterns with roughly perpendicular orientation at 126.3 °C. These surface patterns coarsen under further heating to 126.9 °C. The LEEM image is dominated in the ferroelectric state by intersections of ferroelastic/ferroelectric 90° walls and the surface. The intersection lines are charged.

Domaines: Physique [physics]

N. Barrett, J. Dionot, D. Martinotti, E. Salje, C. Mathieu. Evidence for a surface anomaly during the cubic-tetragonal phase transition in BaTiO 3 (001). Applied Physics Letters, 2018, 113 (2), ⟨10.1063/1.5030498⟩. ⟨hal-01872198⟩