Adsorbate-induced spin-polarization enhancement of Fe3O4(0 0 1)
Adsorbate-induced spin-polarization enhancement of Fe3O4(0 0 1)
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DOI：
10.1088/0022-3727/44/6/064010
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发表时间：
2011-02
期刊：
影响因子：
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通讯作者：
A. Pratt;M. Kurahashi;X. Sun;Y. Yamauchi
中科院分区：
文献类型：
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作者：
A. Pratt;M. Kurahashi;X. Sun;Y. Yamauchi
用自旋极化亚稳氦束研究了在MgO（0 0 1）衬底上制备的清洁的、氢封端的和苯吸附的Fe 3 O 4（0 0 1）薄膜表面的自旋极化。对于干净的表面，一个小的负不对称检测到的氦-电子自旋平行和反平行的样品磁化方向对齐的喷射电子产率。这证实了较早的实验结果，从表面不敏感的技术表明，在表面的Fe 3 O 4（0 0 1）的自旋极化大大减少，从体值，而且，意味着多数自旋状态实际上占主导地位的费米能级。然而，当氢终止时，不对称性大大增强，并且突出了表面吸附和钝化在自旋电子材料的发展中将发挥的重要作用。最简单的π-共轭分子苯在干净的Fe 3 O 4（0 0 1）表面上的吸附进一步证明了这一点，在该表面上观察到类似的自旋极化增强，这种效应可以证明对有机自旋电子器件的设计和制造是有益的。
Using a spin-polarized metastable helium beam, we have investigated the remanent spin polarization at the surface of clean, hydrogen-terminated and benzene-adsorbed Fe3O4(0 0 1) thin films prepared on MgO(0 0 1) substrates. For the clean surface, a small negative asymmetry is detected in the ejected electron yields for helium-electron spins aligned parallel and anti-parallel to the sample magnetization direction. This confirms earlier experimental results from less surface-sensitive techniques which show that the spin polarization at the surface of Fe3O4(0 0 1) is much reduced from the bulk value and, furthermore, implies that majority-spin states actually dominate at the Fermi level. However, when hydrogen-terminated, the asymmetry is considerably enhanced and positive highlighting the important role that surface adsorption and passivation will play in the development of spintronic materials. This is further demonstrated for the adsorption of the simplest π-conjugated molecule, benzene, at the clean Fe3O4(0 0 1) surface where a similar enhancement in the spin polarization is observed, an effect that could prove beneficial to the design and fabrication of organic spintronic devices.