Ferroelectric Thin Films of Deuterated Betaine Arsenate

Abstract

Ferroelectric thin films of partially deuterated betaine arsenate have been grown by evaporation method on NdGaO₃ and α-Al₂O₃ substrates. The films consist of small single-crystal blocks, in which ferroelastic domains have been visualized by polarizing microscope. X-ray diffraction shows that the blocks form a polycrystalline structure of film. Ferroelectric phase transition in DBA films is followed by dielectric anomaly and appearance of dielectric hysteresis loops. The magnitude of dielectric anomaly is small as compared with DBA single crystals. Small value of anomaly is associated with polycrystalline structure of DBA films. The deuteration degree of betaine arsenate films is smaller than that of crystals used for film preparation due to substitution of deuterium by hydrogen ions during the crystallization process.

Keywords:

• Amino acid ferroelectrics
• thin films
• phase transitions