%0 Journal Article
%K Energy
%K Electrochemistry
%K Global climate
%K Unclassified drug
%K Electric field
%K Article
%K Chemical structure
%K Priority journal
%K Bismuth
%K Ferrite
%K Piezoelectricity
%K Bismuth ferrite
%K Electricity generation
%K Electromagnetic field
%K Bismuth derivative
%K Surface property
%K Morphotype
%K Molecular mechanics
%A R.J Zeches
%A M.D Rossell
%A J.X Zhang
%A A.J Hatt
%A Q He
%A C.-H Yang
%A A Kumar
%A C.H Wang
%A A Melville
%A C Adamo
%A G Sheng
%A Y.-H Chu
%A J.F Ihlefeld
%A R Erni
%A C Ederer
%A V Gopalan
%A L.Q Chen
%A D.G Schldin
%A N.A Spaldin
%A L.W Martin
%A Ramamoorthy Ramesh
%B Science
%D 2009
%G eng
%P 977-980
%R 10.1126/science.1177046
%T A strain-driven morphotropic phase boundary in bifeO3
%V 326
%X Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO3) films. Electric field-dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.