41. Growth and Characterization of Relaxor Ferroelectric Thin Films

Epitaxial growth and dielectric characterization of atomically smooth 0.5Ba(Zr_0.2Ti_0.8)O₃–0.5(Ba_0.7Ca_0.3)TiO₃ thin films

Yang Liu, Zheng Wang, Arashdeep Singh Thind, Thomas Orvis, Debarghya Sarkar, Rehan Kapadia, Albina Y. Borisevich, Rohan Mishra, Asif Islam Khan, and Jayakanth Ravichandran Journal of Vacuum Science & Technology A, 37, 011502 (2019)

The authors report the epitaxial growth and the dielectric properties of relaxor ferroelectric 0.5Ba(Zr_0.2Ti_0.8)O₃–0.5(Ba_0.7Ca_0.3)TiO₃ thin films with atomically flat surface on GdScO₃ single crystal substrates. The authors studied the effects of growth conditions, such as the substrate temperature and the oxygen pressure on the structure of the thin films, as measured by x-ray diffraction, to identify the optimal growth conditions. The authors achieved sustained layer-by-layer growth of 0.5Ba(Zr_0.2Ti_0.8)O₃–0.5(Ba_0.7Ca_0.3)TiO₃ films as monitored by in situ and real time reflective high energy electron diffraction. Atomic force microscopy investigations showed atomically smooth step terrace structures. Aberration-corrected scanning transmission electron microscopy images show good epitaxial relation of the film and the substrate without any line defects. High dielectric constant (∼1400) and slim hysteresis loops in polarization-electric field characteristics were observed in 0.5Ba(Zr_0.2Ti_0.8)O₃–0.5(Ba_0.7Ca_0.3)TiO₃ films, which are characteristic of relaxor-type ferroelectric materials.