Stress-induced phase transformations in ⟨001⟩-oriented Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 crystals: Bilinear coupling of ferroelastic strain and ferroelectric polarization

The strain-stress ( k- σ) response characteristics of d001 -oriented crystals of Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 have been investigated. A stress-induced ferroelastic transformation has been observed under uniaxial stress. The k- σresponse was fitted with a Landau phenomenological model based upon a bilinear gradient coupling between ferroelastic strain and ferroelectric polarization.