Müller Georg M, Walowski Jakob, Djordjevic Marija, Miao Gou-Xing, Gupta Arunava, Ramos Ana V, Gehrke Kai, Moshnyaga Vasily, Samwer Konrad, Schmalhorst Jan, Thomas Andy, Hütten Andreas, Reiss Günter, Moodera Jagadeesh S, Münzenberg Markus
IV. Phys. Institut, Universität Göttingen, D-37077 Göttingen, Germany.
Nat Mater. 2009 Jan;8(1):56-61. doi: 10.1038/nmat2341. Epub 2008 Dec 14.
Knowledge of the spin polarization is of fundamental importance for the use of a material in spintronics applications. Here, we used femtosecond optical excitation of half-metals to distinguish between half-metallic and metallic properties. Because the direct energy transfer by Elliot-Yafet scattering is blocked in a half-metal, the demagnetization time is a measure for the degree of half-metallicity. We propose that this characteristic enables us vice versa to establish a novel and fast characterization tool for this highly important material class used in spin-electronic devices. The technique has been applied to a variety of materials where the spin polarization at the Fermi level ranges from 45 to 98%: Ni, Co(2)MnSi, Fe(3)O(4), La(0.66)Sr(0.33)MnO(3) and CrO(2).
自旋极化知识对于在自旋电子学应用中使用材料至关重要。在这里，我们使用半金属的飞秒光激发来区分半金属和金属特性。由于在半金属中埃利奥特 - 亚费特散射导致的直接能量转移被阻断，退磁时间是半金属性程度的一种度量。我们提出，反之，这一特性使我们能够为用于自旋电子器件的这一极其重要的材料类别建立一种新颖且快速的表征工具。该技术已应用于多种材料，其中费米能级处的自旋极化范围为45%至98%：镍、钴锰硅（Co₂MnSi）、四氧化三铁（Fe₃O₄）、镧锶锰氧化物（La₀.₆₆Sr₀.₃₃MnO₃）和二氧化铬（CrO₂）。
