K -edge magnetic circular dichroism of O in CO/Ni/Cu(001): Dependence on substrate magnetic anisotropy and its interpretation
K -edge magnetic circular dichroism of O in CO/Ni/Cu(001): Dependence on substrate magnetic anisotropy and its interpretation
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CO/Ni/Cu(001) 中 O 的 K 边磁圆二色性：对基底磁各向异性的依赖性及其解释
DOI：
10.1103/physrevb.62.14191
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
T. Ohta
中科院分区：
文献类型：
--
作者：
T. Yokoyama;K. Amemiya;M. Miyachi;Y. Yonamoto;D. Matsumura;T. Ohta
研究了Cu（001）衬底上外延生长的Ni薄膜上吸附的CO分子的K边X射线磁圆二色性（XMCD）。在具有垂直磁各向异性（PMA）的10个单层（ML）Ni中，在O 1 s→ CO2 π* 跃迁处观察到较强的负XMCD信号.由于Ni 3d能级的杂化导致CO 2 π* 轨道被部分填充，这一发现意味着CO 2 π* 轨道磁矩与衬底Ni的磁化强度平行排列.轨道矩是由两个π* 轨道的简并性产生的分子轨道原点决定的。相反，在面内磁化强度为6 ML和厚（> 100 ML）Ni膜的情况下，在CO2 π ~* 共振处的XMCD信号很弱且为正.虽然在面内磁化的情况下，轨道矩的起源还不清楚，但这表明轨道矩与Ni呈反平行排列。用CO和Ni之间的化学键框架解释了PMA中CO2 π* 轨道矩的方向。
O K-edge x-ray magnetic circular dichroism (XMCD) was investigated for molecular CO adsorbed on Ni thin films grown epitaxially on Cu (001). In the case of 10 monolayer (ML) Ni that shows perpendicular magnetic anisotropy (PMA), a relatively strong negative XMCD signal was observed at the O 1 s→ CO 2 π* transition. Since the CO 2 π* orbital is partially filled due to hybridization of Ni 3 d levels, this finding implies parallel alignment of the CO 2 π* orbital moment with substrate Ni magnetization. The orbital moment is ascribed to the molecular orbital origin that is derived from degeneracy of the two π* orbitals. On the contrary, in the cases of in-plane magnetization of 6 ML and thick (> 100 ML) Ni films, the XMCD signal at the CO 2 π* resonance was found to be weak and positive. Although the origin of the orbital moment is not yet clear in the in-plane magnetization case, this indicates that the orbital moment shows antiparallel alignment with Ni. The direction of the CO 2 π* orbital moment in PMA is interpreted with a framework of chemical bonding between CO and Ni.