OXIDE NANOMATERIALS WITH PROPERTIES ABSENT IN BULK (AUTHOR REVIEW)

Abstract

A ferroelectric phase can be induced in otherwise nonferroelectric binary oxides like BaO, EuO, and Er₂O₃ by a strong enough intrinsic surface stress present under the curved surface in nanowires. Our analytical calculations performed within the Landau–Ginzburg–Devonshire theory prove that BaO nanowires can be ferroelectric at room temperatures. Undoped nanoparticles of incipient ferroelectrics SrTiO₃ and KTaO₃ without any magnetic ions can become ferromagnetic even at room temperatures due to the presence of a new type of magnetic defects, such as oxygen vacancies, inherent to nanostructures. Nanosized EuO_xSr_1–xTiO₃ wires and tubes are shown to be the new multiferroics with “triple” the antiferrodistortive–ferroelectric–ferromagnetic phase, which is of interest for fundamental study and can be important for their potential applications. We hope that our predictions will stimulate experimental studies of the nanosized binary oxides and perovskites.