In Situ Imaging of Domain Structure Evolution in LaBGeO5 Single Crystals

Crystals

Ilya Shnaidshtein¹  Evgenii Milov¹  Maxim Nebogatikov²  Constantine Plashinnov²  Andrey Akhmatkhanov²  Vladimir Shur² 

[1] Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia;School of Natural Sciences and Mathematics, Ural Federal University, Ekaterinburg 620000, Russia;

关键词: ferroelectric;    Cherenkov second harmonic generation;    domain kinetics;    domain shape;    domain imaging;    domain merging;   

DOI  :  10.3390/cryst10070583

来源: DOAJ

【 摘 要 】

LaBGeO₅ (LBGO) crystals are unique ferroelectric materials for manufacturing highly efficient UV laser sources based on frequency conversion. This is due to their low cut-off wavelength, high nonlinear-optical coefficients, and non-hygroscopicity. Periodical poling requires a deep study of domain kinetics in these crystals. Domain imaging by Cherenkov second harmonic generation microscopy was used to reveal the main processes of domain structure evolution: (1) growth and merging of isolated domains, (2) growth of stripe domains formed on the artificial linear surface defects, and (3) domain shrinkage. In a low field, growth of triangular domains and fast shape recovery after merging were observed, while in a high field, the circular domains grew independently after merging. The revealed essential wall motion anisotropy decreased with the field. The anisotropy led to significant shape transformations during domain shrinkage in low field. The formation of short-lived triangular domains rotated by 180 degrees with respect to the growing isolated domains was observed. The obtained results were explained within the kinetic approach to domain structure evolution based on the analogy between the growth of crystals and ferroelectric domains, taking into account the gradual transition from determined nucleation in low field to the stochastic one in high field.

【 授权许可】

Unknown