Simultaneous control of ferromagnetism and ferroelasticity by oxygen octahedral backbone stretching

Abstract Coexistence of ferromagnetism and ferroelasticity in a single material is an intriguing phenomenon, but has been rarely found. Here we studied both the ferromagnetism and ferroelasticity in a group of LaCoO 3 films with systematically tuned atomic structures. We found that all films exhibit ferroelastic domains with four-fold symmetry and the larger domain size (higher elasticity) is always accompanied by stronger ferromagnetism. We performed synchrotron x-ray diffraction studies to investigate the backbone structure of the CoO 6 octahedra, and found that both the ferromagnetism and the elasticity are simultaneously enhanced when the in-plane Co–O–Co bond angles are straightened. Therefore the study demonstrates the inextricable correlation between the ferromagnetism and ferroelasticity mediated through the octahedral backbone structure, which may open up new possibilities to develop multifunctional materials.