Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia, 26506, USA.
Department of Physics, University of California, Santa Cruz, California, 95064, USA.
Sci Rep. 2017 Aug 3;7(1):7182. doi: 10.1038/s41598-017-07834-0.
The NaMnF fluoride-perovskite has been found, theoretically, to be ferroelectric under epitaxial strain becoming a promising alternative to conventional oxides for multiferroic applications. Nevertheless, this fluoroperovskite has not been experimentally verified to be ferroelectric so far. Here we report signatures of room temperature ferroelectricity observed in perovskite NaMnF thin films grown on SrTiO. Using piezoresponse force microscopy, we studied the evolution of ferroelectric polarization in response to external and built-in electric fields. Density functional theory calculations were also performed to help understand the strong competition between ferroelectric and paraelectric phases as well as the profound influences of strain. These results, together with the magnetic order previously reported in the same material, pave the way to future multiferroic and magnetoelectric investigations in fluoroperovskites.
理论上，NaMnF 氟化物钙钛矿在外延应变下表现为铁电体，有望成为传统氧化物在多铁性应用中的替代品。然而，到目前为止，这种氟钙钛矿还没有实验验证是铁电体。在这里，我们报告了在 SrTiO 上生长的钙钛矿 NaMnF 薄膜中观察到的室温铁电性的特征。我们使用压电力显微镜研究了铁电极化在外电场和内置电场作用下的演化。还进行了密度泛函理论计算，以帮助理解铁电相与顺电相之间的激烈竞争以及应变的深远影响。这些结果与同一材料中先前报道的磁有序一起，为氟钙钛矿的未来多铁性和磁电研究铺平了道路。
