Antoniak C, Lindner J, Spasova M, Sudfeld D, Acet M, Farle M, Fauth K, Wiedwald U, Boyen H-G, Ziemann P, Wilhelm F, Rogalev A, Sun Shouheng
Experimentalphysik-AG Farle, Fachbereich Physik, Universität Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany.
Phys Rev Lett. 2006 Sep 15;97(11):117201. doi: 10.1103/PhysRevLett.97.117201. Epub 2006 Sep 13.
X-ray absorption and magnetic circular dichroism spectra at both the Fe and Pt L(3,2) edges were measured on wet-chemically synthesized monodisperse Fe(50)Pt(50) particles with a mean diameter of 6.3 nm before and after complete removal of the organic ligands and the oxide shell covering the particles by soft hydrogen plasma resulting in a pure metallic state. After thermal treatment of the metallic particles, the coercive field increased by a factor of 6, the orbital magnetic moment at the Fe site increased by 330% and is reduced at the Pt site by 30%, while the effective spin moments did not change. A decrease of the frequency of oscillations in the extended x-ray absorption fine structure at the Pt L(3,2) edges provides evidence for crystallographic changes towards the L1(0) phase.
在通过软氢等离子体完全去除覆盖颗粒的有机配体和氧化壳从而得到纯金属态之前和之后，对平均直径为6.3 nm的湿化学合成单分散Fe(50)Pt(50)颗粒进行了Fe和Pt L(3,2)边缘处的X射线吸收和磁圆二色光谱测量。对金属颗粒进行热处理后，矫顽场增加了6倍，Fe位点的轨道磁矩增加了330%，而Pt位点的轨道磁矩减少了30%，而有效自旋矩没有变化。Pt L(3,2)边缘处扩展X射线吸收精细结构中振荡频率的降低为向L1(0)相的晶体学变化提供了证据。
