Thick lead-free ferroelectric films with high Curie temperatures through nanocomposite-induced strain
- 3 July 2011
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nature Nanotechnology
- Vol. 6 (8), 491-495
- https://doi.org/10.1038/nnano.2011.98
Abstract
Ferroelectric materials are used in applications ranging from energy harvesting to high-power electronic transducers1. However, industry-standard ferroelectric materials contain lead, which is toxic and environmentally unfriendly2. The preferred alternative, BaTiO3, is non-toxic and has excellent ferroelectric properties, but its Curie temperature of ∼ 130 °C is too low to be practical3. Strain has been used to enhance the Curie temperature of BaTiO3 (ref. 4) and SrTiO3 (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 BaTiO3 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 Sm2O3 throughout the film thickness. The columns, which are 10 nm in diameter, strain the BaTiO3 matrix by 2.35%, forcing it to maintain its tetragonal structure and resulting in the highest BaTiO3 transition temperatures so far.Keywords
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