title: Nonlinear phenomena in multiferroic nanocapacitors: joule heating and electromechanical effects.
abstract: We demonstrate an approach for probing nonlinear electromechanical responses in BiFeO(3) thin film nanocapacitors using half-harmonic band excitation piezoresponse force microscopy (PFM). Nonlinear PFM images of nanocapacitor arrays show clearly visible clusters of capacitors associated with variations of local leakage current through the BiFeO(3) film. Strain spectroscopy measurements and finite element modeling point to significance of the Joule heating and show that the thermal effects caused by the Joule heating can provide nontrivial contributions to the nonlinear electromechanical responses in ferroic nanostructures. This approach can be further extended to unambiguous mapping of electrostatic signal contributions to PFM and related techniques.
authors.affiliation: The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. kimy4@ornl.gov
authors.forename: Yunseok
authors.initials: Y
authors.lastname: Kim
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.forename: Alexander
authors.initials: A
authors.lastname: Tselev
authors.forename: Ivan I
authors.initials: II
authors.lastname: Kravchenko
authors.forename: Hee
authors.initials: H
authors.lastname: Han
authors.forename: Ionela
authors.initials: I
authors.lastname: Vrejoiu
authors.forename: Woo
authors.initials: W
authors.lastname: Lee
authors.forename: Dietrich
authors.initials: D
authors.lastname: Hesse
authors.forename: Marin
authors.initials: M
authors.lastname: Alexe
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Kalinin
authors.forename: Stephen
authors.initials: S
authors.lastname: Jesse