Fabrication of La2Ti2O7 nanostructures by focused Ga3+ ion beam and characterization by piezoresponse force microscopy

(012)-oriented lead-free La₂Ti₂O₇ thin films with the monoclinic/perovskite layered structure have been grown by a solgel route on (100)-oriented doped Nb:SrTiO₃ substrates. On nanoscale, both poling experiments performed via the tip of atomic force microscope and the existence of local piezoloops within the domains confirm the piezo-/ferro-electric behaviour of the films. Islands in the lateral range 300-500 nm have been fabricated by focused Ga³⁺ ion beam etching on platinum top electrode. As measured on piezoloops, electromechanical activity within the islands is shown to be similar to the one obtained for the virgin film; no piezoelectric degradation for La₂Ti₂O₇ islands is highlighted. These results confirm that La₂Ti₂O₇ is a highly resistant oxide to ion-beam irradiation. La₂Ti₂O₇ could be considered as a material of choice for the realization of lead-free piezoelectric nanostructures.