Giant room temperature compression and bending in ferroelectric oxide pillars

• Published in: Nature communications 2022-01, Vol.13 (1), p.335-335, Article 335
• Main Authors: Liu, Ying, Cui, Xiangyuan, Niu, Ranming, Zhang, Shujun, Liao, Xiaozhou, Moss, Scott D., Finkel, Peter, Garbrecht, Magnus, Ringer, Simon P., Cairney, Julie M.
• Format: Article
• Language: English
• Subjects: 147/135; 147/143; 639/301/1005/1007; 639/301/1005/1009; Bonding strength; Ceramics; Compression; Deformation; Ductile-brittle transition; Elasticity; Ferroelectricity; First principles; Humanities and Social Sciences; Lead; Lead titanates; Materials science; Mechanical properties; Mechanical tests; Metals; multidisciplinary; Nanoelectromechanical systems; Oxygen; Perovskites; Plastic deformation; Plastic properties; Plasticity; Plastics; Room temperature; Science; Science (multidisciplinary); Strain; Vacancies
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-27952-2

Plastic deformation in ceramic materials is normally only observed in nanometre-sized samples. However, we have observed high levels of plasticity (>50% plastic strain) and excellent elasticity (6% elastic strain) in perovskite oxide Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 , under compression along pc pillars up to 2.1 μm in diameter. The extent of this deformation is much higher than has previously been reported for ceramic materials, and the sample size at which plasticity is observed is almost an order of magnitude larger. Bending tests also revealed over 8% flexural strain. Plastic deformation occurred by slip along {110}  . Calculations indicate that the resulting strain gradients will give rise to giant flexoelectric polarization. First principles models predict that a high concentration of oxygen vacancies weaken the covalent/ionic bonds, giving rise to the unexpected plasticity. Mechanical testing on oxygen vacancies-rich Mn-doped Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 confirmed this prediction. These findings will facilitate the design of plastic ceramic materials and the development of flexoelectric-based nano-electromechanical systems. In materials science, it is a well-accepted fact that metals are generally ductile, and ceramics are always brittle. Here, the authors observe high level of plasticity and excellent elasticity in perovskite oxide under compression and bending with diameter of 2.1 μm.