Ferroelectricity of PZT-based Thin Films Doped with Mn and Nb

摘要

The ternary compound thin films doped with Mn and Nb, Pb(Mn1/3,Nb2/3)O_3-PbZrO_3-PbTiO_3(PMnN-PZ-PT), with the same ratio of PZ/PT=52:48(PZT(52/48)) are fabricated on the heterostructure substrates of SrRuO_3(SRO)/Pt(111)/Ti/SiO_2/Si(100) by the radio frequency (RF) magnetron sputtering system, in which the quench method is used for the post heat treatments. The ternary compound films exhibit polycrystal phase combined with (001), (101) and (111) orientations with the 6% mole percent mixing ratio of PMnN, in which the (111) directions are the main orientations for non-mixed PZT(52/48) films and 6% mole percent PMnN mixing PZT(52/48) films(6%PMnN-94%PZT(52/48)), and so both of them are epitaxially grown on Silicon substrates with the (111) orientation. The ferroelectricities of the films are studied by the Sawyer Tower circuit, and the results show that the mixing of PMnN seriously improves the ferroelectricities of PZT(52/48), in which the 6% mixed PZT films own the rest polarization intensity p_r = 23.7μC/m~2, the saturation polarization intensity p_s = 40μC/m~2 and the coercive electric-field intensity E_c =139 kV/cm which are distinctly larger than the non-mixed PZT(52/48) films