The influence of stress and size effects on the ferroelectric or dielectric property of PbTiO_3 (PTO) (ultrathin) films by using Landau-Devonshire theory is discussed.

• 用推广的Landau Devonshire理论研究了应力与尺寸效应对PbTiO3(PTO)薄膜的铁电/介电性质的影响.