Negative-pressure-induced enhancement in a freestanding ferroelectric
by Jin Wang, Ben Wylie-van Eerd, Tomas Sluka, Cosmin Sandu, Marco Cantoni, Xian-KuiWei, Alexander Kvasov, Leo John McGilly, Pascale Gemeiner, Brahim Dkhil, Alexander Tagantsev, Joe Trodahl, and Nava Setter
Ferroelectrics are widespread in technology, being used in electronics and communications, medical diagnostics and industrial automation. However, extension of their operational temperature range and useful properties is desired. Recent developments have exploited ultrathin epitaxial films on lattice-mismatched substrates, imposing tensile or compressive biaxial strain, to enhance ferroelectric properties. Much larger hydrostatic compression can be achieved by diamond anvil cells, but hydrostatic tensile stress is regarded as unachievable. Theory and ab initio treatments predict enhanced properties for perovskite ferroelectrics under hydrostatic tensile stress.
In the present study researchers from the Swiss Federal Institute of Technology in Lausanne, Tsinghua University in Shenzhen, Victoria Univerity of Wellington the Ecole Centrale Paris and the Ernst Ruska-Centre in Jülich report on a negative-pressure-driven enhancement of the tetragonality, Curie temperature and spontaneous polarisation in freestanding PbTiO3 nanowires, driven by stress that develops during transformation of the material from a lower-density crystal structure to the perovskite phase. This study suggests a simple route to obtain negative pressure in other materials, potentially extending their exploitable properties beyond their present levels.
Jin Wang, Ben Wylie-van Eerd, Tomas Sluka, Cosmin Sandu1, Marco Cantoni, Xian-KuiWei, Alexander Kvasov, Leo John McGilly, Pascale Gemeiner, Brahim Dkhil, Alexander Tagantsev, Joe Trodahl, and Nava Setter: Negative-pressure-induced enhancement in a freestanding ferroelectric, Nature Materials 14 (2015) 985-990.