%0 Journal Article
%K Phase transitions
%K Defects
%K Polarization
%K Electric field effects
%K Thermodynamics
%K Hysteresis loops
%K Spectroscopic analysis
%K Built-in fields
%K Electrochemical reactions
%K Pinning centers
%K Polarization reversal
%A S.V Kalinin
%A S Jesse
%A B.J Rodriguez
%A Y.H Chu
%A Ramamoorthy Ramesh
%A E.A Eliseev
%A A.N Morozovska
%B Physical Review Letters
%D 2008
%G eng
%R 10.1103/PhysRevLett.100.155703
%T Probing the role of single defects on the thermodynamics of electric-field induced phase transitions
%V 100
%X The kinetics and thermodynamics of first order transitions are universally controlled by defects that act as nucleation sites and pinning centers. Here we demonstrate that defect-domain interactions during polarization reversal processes in ferroelectric materials result in a pronounced fine structure in electromechanical hysteresis loops. Spatially resolved imaging of a single defect center in multiferroic BiFeO3 thin film is achieved, and the defect size and built-in field are determined self-consistently from the single-point spectroscopic measurements and spatially resolved images. This methodology is universal and can be applied to other reversible bias-induced transitions including electrochemical reactions. © 2008 The American Physical Society.