Physico-Chemical nanomaterials science

Peculiarities of ferroelastoelectric domain structure and nanocrystals’ growth on the surface of [(CH3)2CHNH3]4Cd3Cl10 crystal
Chornii Yu., Kapustianyk V., Eliyashevskyy Yu., Serkiz R. 
Department of Physics, Ivan Franko National University of Lviv, Dragomanova str. 50, 79005 Lviv, Ukraine.
E-mail: ychornii@gmail.com

This work is devoted to study of ferroelastoelectric domain structure and peculiarities of nano- and microcrystals growth on the surface of [(CH3)2CHNH3]4Cd3Cl10 (IPACC) crystals. The domains in the ferroelastoelectric phase lying below 294 K were visualized using AFM. In the contact mode we observed a regular pattern of the parallel strips with an average thickness of nearly 1 µm that would be considered as domains. Moreover, the surface of the crystal was found to be modulated with an amplitude close to 1 nm. The neighboring domains should differ by their optical characteristics, first of all, by the refractive indices due to a different sign of the electrooptic effect. Due to this IPACC crystals would be used as a diffraction grating with a period close to 1 µm.
It was shown that the surface morphology of IPACC crystals kept for a long time (from one up to twelve months) in the open air with a high humidity undergoes the considerable changes in comparison with the freshly cleaved samples. The samples are characterized by growth of the nanocrystals on the first stage and the larger microcrystals on the next stages of the sample aging. Another types of the elements observed on the surface were the nano- or microrods. The model describing the peculiarities of surface morphology and domain structure modification arising in the process of aging was proposed.
It is interesting to note that no similar processes of aging were detected in IPACCC crystals doped with copper [1]. Due to this such materials look more suitable for the mentioned practical applications.

1.	V. Kapustianyk, Z. Czapla, V. Rudyk, Yu. Eliyashevskyy, P. Yonak, S. Sveleba. Domain structure and birefringent properties of [(CH3)2CHNH3]4Cd3Cl10:Cu crystals in the region of their phase transitions // Ferroelectrics.-2019.-540, N 1.-P. 212-221.