Chuanshou Wang 1 , Xiaoxing Ke 2 , 3 , Jianjun Wang 4 , Renrong Liang 5 , Zhenlin Luo 6 , Yu Tian 1 , Di Yi 7 , Qintong Zhang 8 , Jing Wang 1 , Xiu-Feng Han 8 , Gustaaf Van Tendeloo 2 , Long-Qing Chen 4 , 9 , Ce-Wen Nan a , 4 , Ramamoorthy Ramesh b , 7 , Jinxing Zhang c , 1
03 February 2016
A controllable ferroelastic switching in ferroelectric/multiferroic oxides is highly desirable due to the non-volatile strain and possible coupling between lattice and other order parameter in heterostructures. However, a substrate clamping usually inhibits their elastic deformation in thin films without micro/nano-patterned structure so that the integration of the non-volatile strain with thin film devices is challenging. Here, we report that reversible in-plane elastic switching with a non-volatile strain of approximately 0.4% can be achieved in layered-perovskite Bi 2WO 6 thin films, where the ferroelectric polarization rotates by 90° within four in-plane preferred orientations. Phase-field simulation indicates that the energy barrier of ferroelastic switching in orthorhombic Bi 2WO 6 film is ten times lower than the one in PbTiO 3 films, revealing the origin of the switching with negligible substrate constraint. The reversible control of the in-plane strain in this layered-perovskite thin film demonstrates a new pathway to integrate mechanical deformation with nanoscale electronic and/or magnetoelectronic applications.
Ferroelastic switching in thin films is typically restricted by constraints from the substrate or occurs around twin-like domains. Here, the authors show reversible and non-volatile ferroelastic switching avoiding substrate constraints in layered-perovskite Bi_2WO_6 epitaxial films.