Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5423263 | Surface Science | 2010 | 5 Pages |
Abstract
Spin polarized field emission from thin film Fe- and Co-coated W(001) and W(111) tips has been investigated. A transverse spin polarization component is detected in each case. For W(111) tips, the azimuthal orientation of polarization showed only a weak preference for the set of ã1Ì
10ã and ã112Ì
ã tip directions due to the competing influence of magnetocrystalline anisotropy and tip morphology on tip magnetization. On the contrary, the polarization direction for W(001) tips exhibited a strong preference for alignment with the transverse low-index crystallographic directions, i.e. the ã110ã for Co and ã100ã for Fe. Superparamagnetic fluctuations of the tip magnetization are evident in the polarization direction of emitted electrons when film coatings are very thin. At marginally larger thickness, long-term stability of the polarization magnitude and direction is observed at 300Â K. A method for changing the stable spin polarization direction is also presented that exploits spontaneous flipping of the tip magnetization at elevated temperature.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Y.R. Niu, M.S. Altman,