Polarization coupling in epitaxial ZnO / BaTiO_3 thin film heterostructures on SrTiO_3 (100) substrates

摘要

Strong polarization coupling is expected by combining ferroelectric materials with switchable polarization and wurtzite layers exhibiting a permanent spontaneous polarization. To demonstrate these charge coupling effects, current-voltage, conductivity-frequency and capacitance-frequency (admittance) characteristics have been measured on epitaxial heterostructures grown of ferroelectric BaTiO_3 (001) films on conducting SrRuO_3 layers on SrTiO_3 (100) substrates with oxide SrRuO_x, metallic Pt and semiconducting ZnO top electrodes. The electrical measurements show clear indications for polarization coupling of the ferroelectric perovskite BaTiO_3 and the piezoelectric wurtzite ZnO thin films.