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Domain Wall Dynamics in Epitaxial Ferroelectric Thin Films in Investigated by Piezoresponse Force Microscopy

CNM Nanoscience Seminar
Sang Mo Yang, Seoul National University
December 4, 2012 10:30AM to 11:30AM
Building 440, Room A105-106
Ferroelectric (FE) materials are fascinating and practical because of the spontaneous polarization which is strongly coupled to long-range electric and stress fields, leading to outstanding properties (e.g., switchablity of electrical polarization and piezoelectricity). Based on such captivating properties, it has been numerous efforts to develop the advanced FE-based electronic devices. The performance of FE-based devices is mainly determined by the domain dynamics, i.e., the nucleation and subsequent growth of domains.

Therefore, it is imperative to understand FE domain dynamics, especially at the nanoscale level. Here, I present our recent studies on nanoscale visualization of FE domain wall dynamics in epitaxial Pb(Zr,Ti)O3 thin films using modified-piezoresponse force microscopy (PFM) [1]. First, I demonstrate that the domain wall motion in epitaxial FE thin film capacitors can be explained well in terms of nonlinear dynamics of elastic objects in disordered media [2]. Second, I show that time-dependent domain wall pinning process is the primary origin of polarization fatigue [3].

[1] D. J. Kim, J. Y. Jo, T. H. Kim, S. M. Yang et al., Appl. Phys. Lett. 91, 132903 (2007).

[2] S. M. Yang et al., Appl. Phys. Lett. 92, 252901 (2008); J. Y. Jo, S. M. Yang et al., Phys. Rev. Lett. 102, 045701 (2009).; S. M. Yang et al., Curr. Appl. Phys. 11, 1111 (2011).

[3] S. M. Yang et al., Adv. Funct. Mater. 22, 2310 (2012).