title: Thick lead-free ferroelectric films with high Curie temperatures through nanocomposite-induced strain.
abstract: Ferroelectric materials are used in applications ranging from energy harvesting to high-power electronic transducers. However, industry-standard ferroelectric materials contain lead, which is toxic and environmentally unfriendly. The preferred alternative, BaTiO(3), is non-toxic and has excellent ferroelectric properties, but its Curie temperature of ∼130 °C is too low to be practical. Strain has been used to enhance the Curie temperature of BaTiO(3) (ref. 4) and SrTiO(3) (ref. 5) films, but only for thicknesses of tens of nanometres, which is not thick enough for many device applications. Here, we increase the Curie temperature of micrometre-thick films of BaTiO(3) to at least 330 °C, and the tetragonal-to-cubic structural transition temperature to beyond 800 °C, by interspersing stiff, self-assembled vertical columns of Sm(2)O(3) throughout the film thickness. The columns, which are 10 nm in diameter, strain the BaTiO(3) matrix by 2.35%, forcing it to maintain its tetragonal structure and resulting in the highest BaTiO(3) transition temperatures so far.
authors: Department of Materials Science, University of Cambridge, Cambridge, CB2 3QZ, UK. sah59@cam.ac.uk
authors: Sophie A
authors: SA
authors: Harrington
authors: Junyi
authors: J
authors: Zhai
authors: Sava
authors: S
authors: Denev
authors: Venkatraman
authors: V
authors: Gopalan
authors: Haiyan
authors: H
authors: Wang
authors: Zhenxing
authors: Z
authors: Bi
authors: Simon A T
authors: SA
authors: Redfern
authors: Seung-Hyub
authors: SH
authors: Baek
authors: Chung W
authors: CW
authors: Bark
authors: Chang-Beom
authors: CB
authors: Eom
authors: Quanxi
authors: Q
authors: Jia
authors: Mary E
authors: ME
authors: Vickers
authors: Judith L
authors: JL
authors: Macmanus-Driscoll