Ferroelectric domain structures in <001>-oriented K0.15Na0.85NbO3 lead-free single crystal

In this work, ferroelectric domain structures of <001 >-oriented K0.15Na0.85NbO3 single crystal are characterized. Transmission electron microscopy (TEM) observation revealed high-density of laminate domain structures in the crystal and the lattices of the neighboring domains are found to be twisted in a small angle. Superlattice diffraction spots of 12{eeo} and 12{ooe} in electron diffraction patterns are observed in the crystal, revealing the a+a+c− tilting of oxygen octahedral in the perovskite structure. The piezoresponse of domains and in-situ poling responses of K0.15Na0.85NbO3 crystal are observed by piezoresponse force microscopy (PFM), and the results assure its good ferroelectric properties.