Ferroelectric properties of Pb(Mn_1/3Nb_2/3)O₃-Pb(Zr,Ti)O₃ thin films epitaxially grown on (001)MgO substrates

Ferroelectric ternary perovskite thin films of 0.06Pb(Mn_1/3,Nb_2/3)O₃ (PMnN)-0.42PbZrO₃ (PZ)-0.52PbTiO₃ (PT) [0.06PMnN–0.94PZT(45/55)] have been grown on the (001)MgO substrates by radio frequency-magnetron sputtering with quenching processing. The deposition conditions, microstructures, piezoelectric, and ferroelectric properties of the ternary perovskite thin films are described in comparison with the binary compounds of PZ–PT (PZT). The out-plane x-ray diffraction (XRD) measurements for the ternary PMnN–PZT perovskite thin films of 1 to 1-3 μm in film thickness show strong single (001) orientation. The in-plane Φ-scan XRD curve verified the ternary thin films are single crystals of perovskite structure. Their lattice parameters are almost the same as bulk values and the ternary thin films are almost stress free. The PMnN–PZT thin films show high density without columnar structure. The PZT-based ternary perovskite thin films with the small addition of PMnN, i.e., 6 mole % PMnN, exhibit a strong hard ferroelectric response, i.e., P_s=60 μC/cm² and 2E_c=230 kV/cm. Their effective piezoelectric constants are typically e_31,eff=-7.7 C/m². These values are slightly higher than those of binary perovskite PZT thin films_.