Nanoscale polarization relaxation of epitaxial BiFeO3 thin film

• Main Authors: Chen, Weigang, You, Lu, Chen, Gaofeng, Chua, Ngeah Theng, Guan, Ong Hock, Zou, Xi, Wang, Junling, Chen, Lang
• Other Authors: School of Materials Science & Engineering
• Format: Article
• Language: English
• Published: 2011
• Subjects: DRNTU::Engineering::Materials::Microelectronics and semiconductor materials::Thin films
• Online Access: https://hdl.handle.net/10356/90597; http://hdl.handle.net/10220/7400
• Institution: Nanyang Technological University

The polarization relaxation phenomena in a 40-nm-thick epitaxial BiFeO3 thin film grown on a (001) SrTiO3 substrate with SrRuO3 bottom electrode, was studied in nanoscale using dual-frequency resonance-tracking piezoresponse force microscopy. The as-grown film shows highly irregular mosaic domain pattern. The nucleation of reversed domains followed by domain wall propagation and domain coalesce was observed during relaxations. The polarization relaxation follows a stretched exponential model f = 1 - e^(-k(t-t0)^n) with parameters t0 = 2894 s, n =0.50 and k =6.04e-4. Local polar defects act as nucleation centers and the time-dependent depolarization field is the driving force for polarization relaxation.