Are ferroic domains distributed randomly upon their formation?

Doaa Khorshid ^1,2 Asaf Hershkovitz ^1,2 Hemaprabha Elangovan ^1,2 Maya Barzilay ^1,2 Cecile Saguy ² Alp Sehirlioglu ⁵ Liyang Ma ³ Shi Liu ^3,4 Yachin Ivry ^1,2

¹Department of Material science and Engineering, Technion- Israel Institute of Technology, Haifa, Israel
²Solid state institute, Technion- Israel Institute of Technology, Haife, Israel
³Key Laboratory for Quantum Materials of Zhejiang province, School of Science, Westlake University, Zhejiang, China
⁴Institute of Natural Science, Westlake Institute of Advanced Study, Zhejiang, China
⁵Materials Science and Engineering, Case Western Reserve University, Cleveland, Ohio, USA

Ferroelectric domains have an immense technological significance because of their ability to store data. Consequently, understanding the limits of domain engineering is an important task.

Domains formation occurs during the ferroelectric phase transition. It is known that domains are deterministically writable with an external electric field. But how random or fixed is the domain distribution upon their creation in a thermal-induced phase transition?

To address this question, we used a direct observation of the domain distribution, while conducting a periodic thermal-induced phase transition. We showed that the correlation value of domain distributions in different cycles is 81 percent, which is very significant statistically. PFM and TEM data were used to show these results.

Atomic scale TEM measurements indicate that the origin of this repetitiveness is immobile oxygen vacancies that are pinned at the domain walls and do not move even after phase transition. These results of memory effects of the domain wall were obtained also by complementary independent simulations, demonstrating the limits of domain randomness, which is important for data-storage applications.