To find the Electrochemical Impedance Spectroscopy (EIS) of metal oxide coatings sandwiched between two dielectric layers, you'll need a model that reflects both the electrical properties of each layer and their interfaces. This is typically approached using equivalent circuit modeling and measured or simulated using an impedance analyzer.

Aida Ben Jazia Kharrat 's response is accurate. In addition to that, If in case you are wondering how to perform EIS! Apply the AC amplitude of 10mV, if the current response is too weak, then use 50mV. Typically, you have to sweep the frequency from 1 MHz to 100 milli Hz and measure corresponding impedance (real and img). Check this article.

Nanotechnology 31, no. 25 (2020): 255705.

And then you must fit the models. For fitting, you can use software like Zview or the built-in software available in most commercial electrochemical setups. Caution: Not all fits are accurate. The fitted model must explain the physical/chemical phenomenon observed via EIS.