Mean-free path effects in magnetoresistance of ferromagnetic nanocontacts
| Autor: | Useinov, A. N., Tagirov, L. R., Deminov, R. G., Zhou, Y., Pan, G. |
|---|---|
| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | Eur. Phys. J. B 60, 187-192 (2007) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1140/epjb/e2007-00335-8 |
| Popis: | We investigated the mean-free path effects on the magnetoresistance of ferromagnetic nanocontacts. For most combinations of parameters the magnetoresistance monotonously decreases with increasing the contact cross-section. However, for a certain choice of parameters the calculations show non-monotonous behavior of the magnetoresistance in the region in which the diameter of the contact becomes comparable with the mean-free path of electrons. We attribute this effect to different conduction regimes in the vicinity of the nanocontact: ballistic for electrons of one spin projection, and simultaneously diffusive for the other. Furthermore, at certain combinations of spin asymmetries of the bulk mean-free paths in a heterocontact, the magnetoresistance can be almost constant, or may even grow as the contact diameter increases. Thus, our calculations suggest a way to search for combinations of material parameters, for which high magnetoresistances can be achieved not only at the nanometric size of the contact, but also at much larger cross-sections of nanocontacts which can be easier for fabrication with current technologies. The trial calculations of the magnetoresistance with material parameters close to those for the Mumetal-Ni heterocontacts agree satisfactorily with the available experimental data. Comment: 13 pages, 7 figures |
| Databáze: | arXiv |
| Externí odkaz: |
|