“…Ferroelectric thin films are a class of ferroelectric material, which are often based on ferroelectric oxides, such as Pb(Zr,Ti)O3 (Ba,Sr)TiO3 and BiFeO3. [55][56][57][58] Fabrication methods for ferroelectric thin-films include radio-frequency (RF) sputtering, metalorganic chemical deposition, electron beam evaporation, pulsed laser deposition and the sol-gel method. The introduction of porosity into ferroelectric thin films can enhance the piezoelectric response, since the introduction of porosity can eliminate the clamping effects of the substrate and make the ferroelectric domain walls mobile.…”