Applying uniform reversible strain to epitaxial oxide films

We demonstrate using four-circle x-ray diffraction that the piezoelectric substrate of Pb(Mg1/3Nb2/3)(0.72)Ti0.28O3(001) induces uniform reversible in-plane strain to epitaxially-grown oxide films and bilayers. The biaxial in-plane strain depends linearly on the applied electrical voltage. Utilizing the reversible strain, the strain-dependent lattice structure and the Poisson number characterizing the elastic response is determined for 200 nm thick SrTiO3, LaScO3, and BiFeO3 films. The uniformity and reversibility of the strain provides access to the direct quantitative measurement of strain-dependent properties of epitaxial oxide films.