Spin- and time-resolved photoemission studies of thin Co2FeSi Heusler alloy films

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:316

Article; Proceedings Paper

Wuestenberg, J.-P. ; Cinchetti, M. ; Albaneda, M. Sánchez ; Bauer, M. ; Aeschlimann, M.

关键词: CFS;    Heusler;    spin polarization;    spin filter effect;    photoemission;    spintronics;    escape depth;   

DOI  :  10.1016/j.jmmm.2007.02.164

来源: Elsevier

【 摘 要 】

We have studied the possibly half-metallic Co2FeSi full Heusler alloy by means of spin- and time-resolved photoemission spectroscopy. For excitation, the second and fourth harmonic of femtosecond Ti:sapphire lasers were used, with photon energies of 3.1 and 5.9 eV, respectively. We compare the dependence of the measured surface spin polarization (SSP) on the particular photoemission mechanism, i.e. 1-photon photoemission (1PPE) or 2-photon photoemission (2PPE). The observed differences in the spin polarization can be explained by a spin-dependent lifetime effect occurring in the 2-photon absorption process. The difference in escape depth of the two methods in this context suggests that the observed reduction of spin polarization (compared to the bulk) cannot be attributed just to the outermost surface layer but takes place at least 4-6nm away from the surface. (c) 2007 Elsevier B.V. All rights reserved.

【 授权许可】

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