Effect of correlated oxide electrodes on disorder pinning and thermal roughening of ferroelectric domain walls in epitaxial PbZr_0.2Ti_0.8O₃ thin films

Authors

Kun Wang, University of Nebraska-LincolnFollow
Yifei Hao, University of Nebraska-LincolnFollow
Le Zhang, University of Nebraska-Lincoln
Yuanyuan Zhang, University of Nebraska-LincolnFollow
Xuegang Chen, University of Nebraska-Lincoln
Xia Hong, University of Nebraska-LincolnFollow

Date of this Version

7-9-2021

Citation

WANG, HAO, ZHANG, ZHANG, CHEN, AND HONG. PHYSICAL REVIEW MATERIALS 5, 074402 (2021). DOI: 10.1103/PhysRevMaterials.5.074402

Comments

Used by permission.

Abstract

We report the competing effects of disorder pinning and thermal roughening on ferroelectric domain walls as a function of temperature in epitaxial PbZr_0.2Ti_0.8O₃ thin films deposited on (001) SrTiO₃ substrates buffered by three types of correlated oxide electrodes, La_0.67Sr_0.33MnO₃, LaNiO₃, and SrIrO₃. Piezoresponse force microscopy studies show that the 50-nm PbZr_0.2Ti_0.8O₃ films are uniformly polarized in the as-grown states, with the patterned domain structures persisting above 700 °C. For all three types of films, the domain wall roughness is dominated by two-dimensional (2D) random bond disorder at room temperature, and transitions to 1D thermal roughening upon heating. The roughness exponent ζ increases progressively from 0.3 to 0.5 within a temperature window that depends on the bottom conducting oxide type, from which we extracted the distribution of disorder pinning energy. We discuss the possible origins of the disorder pinning and the effect of the correlated oxide electrodes on the energy landscape of DW motion.