Crack resistance of bismuth ferrite films obtained on a flexible substrate

¹ Dagestan State University, Makhachkala, St. M. Gadjieva 43-a, Dagestan Republic, 367000, Russia
² The Technical University of Cluj-Napoca, Constantin Daicoviciu Street, no. 15, Cluj-Napoca, 400020, Cluj county, Romania
³ Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, Brno 616 62, Czech Republic
⁴ Brno University of Technology, Faculty of Electrical Engineering and Communication, Department of Physics, Technicka 2848/8, Brno 61600, Czech Republic
⁵ Dagestan State Technical University, Makhachkala, St. I. Shamil, 70, Dagestan Republic, 367026, Russia
⁶ Brno University of Technology, Central European Institute of Technology, Purkyňova 123, 612 00 Brno, Czech Republic
⁷ Ural State University of Economics, Institute of management and information technologies, Russian Federation

^* Corresponding author: stefan_ta@yahoo.com

Abstract

Ultrathin BiO_x and FeO_x layers were obtained by Atomic Layer Deposition (ALD) on the surface of a flexible Kapton substrate (poly (4,4’-oxydiphenylene-pyromellitimide)) at a temperature of 250 °C. The layer thickness was 50 - 100 nm. Surface morphology, electrical polarization, and mechanical properties were investigated by Atomic Force Microscope, Piezoelectric Force Microscopy and Force Modulation Microscopy. Chemical analysis was performed by X-ray Photoelectron Spectroscopy, where the formation of Bi2O₃ and Fe2O₃ phases, as well as intermediate phases in the Bi-Fe-O system, was observed. With a small increase in the Bi content of the film, the BFO / Kapton structure becomes more crack resistant. Modification of the Kapton surface with bismuth and iron oxides showed that such a composition exhibits multiferroic behavior.