Charles University in Prague, Faculty of Mathematics and Physics, Prague, Czech Republic.
Phys Rev Lett. 2011 Jun 10;106(23):236101. doi: 10.1103/PhysRevLett.106.236101. Epub 2011 Jun 6.
A surface layer ("skin") different from the bulk was found in single crystals of BiFeO(3). Impedance analysis and grazing incidence x-ray diffraction reveal a phase transition at T(*)∼275±5 °C that is confined within the surface of BiFeO(3). X-ray photoelectron spectroscopy and refraction-corrected x-ray diffraction as a function of incidence angle and photon wavelength indicate a reduced electron density and an elongated out-of-plane lattice parameter within a few nanometers of the surface. The skin will affect samples with large surface to volume ratios, as well as devices that rely on interfacial coupling such as exchange bias.
在 BiFeO(3) 的单晶中发现了与体相不同的表面层（“皮层”）。阻抗分析和掠入射 X 射线衍射揭示了在 T(*)∼275±5 °C 发生的局限于 BiFeO(3) 表面的相转变。X 射线光电子能谱和折射校正的 X 射线衍射随入射角和光子波长的函数变化表明，在表面的几个纳米范围内，电子密度降低，面外晶格参数伸长。皮层会影响具有大的表面与体积比的样品，以及依赖于界面耦合的器件，例如交换偏置。
