In situ investigation of electric field and stress control of ferroelectric phases in PIN-PMN-PT single crystal

We explored stability of relaxor ferroelectric single crystals with composition near a morphotropic phase boundary (MPB) using the three-pronged approach offered by this project of in situ, stress, temperature and E field whereby a bias of any one of these parameters can move the operating point in almost any direction.This MPB can be moved through the application of stress or electric field. In this work we demonstrate an induced rhombohedral (R) to orthorhombic (O) phase transition in [011] cut Pb(In_1/2Nb_1/2)O₃-Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃(PIN-PMN-PT) single crystal relaxor ferroelectric, that can be simultaneously tuned through combination of stress and applied electric field. Direct observations of this phase transition with X-ray and Raman scattering reveal the local symmetry while sweeping through the transition with a low applied electric field when the crystal is near a critical value of stress. A coexistence of R and O phases was observed and these microscopic measurements mirror the bulk strain in the sample. Remarkably, cycling through this transition can generate reversible strain >0.35% for tens of millions of cycles with little fatigue. Details of these results and their implications will be presented.