Bismuth calcium niobate film material with periodic nanoscale microcrack structure and preparation method of bismuth calcium niobate film material

The invention provides a bismuth calcium niobate film material with a periodic nanoscale microcrack structure and a preparation method thereof. The preparation method of the bismuth calcium niobate thin film material with the periodic nanoscale microcrack structure adopts a pulse laser deposition method, and comprises the following steps: selecting a single crystal substrate which can enable the thin film to generate tensile stress and has a good lattice matching relationship, and carrying out pulse laser bombardment ablation on a CBN (Cubic Boron Nitride) target material with excessive Bi under the deposition oxygen pressure of 0.1 mbar to 0.2 mbar for deposition, so as to obtain the bismuth calcium niobate thin film material with the periodic nanoscale microcrack structure. And directly cooling under a certain oxygen pressure to obtain the bismuth calcium niobate film material with the periodic nanoscale microcrack structure. Wherein the single crystal substrate is a niobium-doped strontium titanate or stro