The Growth of Polarization Domains in Ultrathin Ferroelectric Films Seeded by the Tip of an Atomic Force Microscope

Mohammad Zamani-Alavijeh; Timothy A Morgan; Andrian V Kuchuk; Gregory J Salamo

doi:10.1186/s11671-022-03688-2

The Growth of Polarization Domains in Ultrathin Ferroelectric Films Seeded by the Tip of an Atomic Force Microscope

Nanoscale Res Lett. 2022 May 12;17(1):52. doi: 10.1186/s11671-022-03688-2.

Authors

Mohammad Zamani-Alavijeh^{1

2}, Timothy A Morgan², Andrian V Kuchuk², Gregory J Salamo^{3

4}

Affiliations

¹ Physics Department, University of Arkansas, Nanoscience Building, 731 West Dickson, Fayetteville, AR, USA.
² Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, USA.
³ Physics Department, University of Arkansas, Nanoscience Building, 731 West Dickson, Fayetteville, AR, USA. salamo@uark.edu.
⁴ Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, USA. salamo@uark.edu.

Abstract

Piezoresponse force microscopy is used to study the velocity of the polarization domain wall in ultrathin ferroelectric barium titanate (BTO) films grown on strontium titanate (STO) substrates by molecular beam epitaxy. The electric field due to the cone of the atomic force microscope tip is demonstrated as the dominant electric field for domain expansion in thin films at lateral distances greater than about one tip diameter away from the tip. The velocity of the domain wall under the applied electric field by the tip in BTO for thin films (less than 40 nm) followed an expanding process given by Merz's law. The material constants in a fit of the data to Merz's law for very thin films are reported as about 4.2 KV/cm for the activation field, [Formula: see text], and 0.05 nm/s for the limiting velocity, [Formula: see text]. These material constants showed a dependence on the level of strain in the films, but no fundamental dependence on thickness.

Keywords: Applied electric field by AFM tip; Merz’s law; Polarization domains.