【摘要】 以生长在不同电极衬底:MgO,c-sapphire,a-sapphire,Si上的钙钛矿PbTiO3(PTO)/Terfenol-D压电/压磁异质结为例,利用唯象热力学理论研究了热应力对压电/压磁异质结磁电耦合效应的影响.计算结果表明,铁电薄膜内的热应力强烈依赖于薄膜沉积温度与衬底、薄膜之间热膨胀系数的差异,而热应力又显著影响磁电耦合性能.对于热膨胀系数大于薄膜材料的衬底,如MgO,铁电薄膜内的热应力为压应力,导致压电/压磁异质结的磁电电压系数增强;对于热膨胀系数小于薄膜材料衬底,如c-sapphire,a-sapphire,Si,铁电薄膜内热应力为拉应力,导致压电/压磁异质结的磁电电压系数减小.研究提出了通过改变沉积温度以及选择合适衬底来调控压电/压磁异质结磁电耦合效应的新思路,为工程上增强压电/压磁异质结磁电耦合性能提供了新的途径.更多还原

【Abstract】 The impact of thermal stress on the magnetoelectric coupling in ferroelectric PbTiO3(PTO)/ferromagnetic Terfenol-D heterostructures was investigated based on Landau-Devonshire thermodynamic model.The results show that magnetoelectric coupling property of the heterostructures depends strongly on the thermal stress in PTO filmsdecided by the deposition temperature TG and the thermal expansion coefficients’ difference between PTO films and substrates.For IC-compatible substrates such as Si,c-sapphire,and a-sapphire that induce tensile in plane thermal stresses,the magnetoelectric coupling of PTO/Terfenol-D heterostructures were decreased.Whereas for PTO films on MgO,compressive thermal in-plane stresses can enhance magnetoelectric coupling.Careful choice of the deposition temperature and the thermal expansion coefficients of the substrates might be used as additional design parameters to achieve desirable magnetoelectric coupling properties of multiferroic heterostructures.更多还原