The la - modified thin films with 220nm thickness exhibited diffuse phase transition through the testing of temperature dependence of dielectric permittivity . the abnormal dielectric phenomenon was explained according to the observed relaxor behavior . the influence of post - annealing on the properties of the ferroelectric thin - film capacitors is another component of this thesis 在薄膜的介电性质方面，通过对介电温谱的测试，发现对于厚度薄至220nm的薄膜，掺镧后同样会导致驰豫型的铁电相变，并依此解释了介电常数的“反常”现象。
