title: Ionically-mediated electromechanical hysteresis in transition metal oxides.
abstract: Nanoscale electromechanical activity, remanent polarization states, and hysteresis loops in paraelectric TiO(2) and SrTiO(3) thin films are observed using scanning probe microscopy. The coupling between the ionic dynamics and incipient ferroelectricity in these materials is analyzed using extended Landau-Ginzburg-Devonshire (LGD) theory. The possible origins of electromechanical coupling including ionic dynamics, surface-charge induced electrostriction, and ionically induced ferroelectricity are identified. For the latter, the ionic contribution can change the sign of first order LGD expansion coefficient, rendering material effectively ferroelectric. The lifetime of these ionically induced ferroelectric states is then controlled by the transport time of the mobile ionic species and well above that of polarization switching. These studies provide possible explanation for ferroelectric-like behavior in centrosymmetric transition metal oxides.
authors: The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. ykim943@gmail.com
authors: Yunseok
authors: Y
authors: Kim
authors: Anna N
authors: AN
authors: Morozovska
authors: Amit
authors: A
authors: Kumar
authors: Stephen
authors: S
authors: Jesse
authors: Eugene A
authors: EA
authors: Eliseev
authors: Fabien
authors: F
authors: Alibart
authors: Dmitri
authors: D
authors: Strukov
authors: Sergei V
authors: SV
authors: Kalinin
mesh_terms: D003198:Computer Simulation; D017097:Electric Impedance; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008956:Models, Chemical; D050997:Nanomedicine; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D013314:Stress, Mechanical; D013324:Strontium / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D014025:Titanium; D013324:Strontium