Abstract.
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 fabriaction 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.
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References
N. García, M. Muñoz, Y.-W. Zhao, Phys. Rev. Lett. 82, 2923 (1999)
G. Tatara, Y.-W. Zhao, M. Muñoz, N. García, Phys. Rev. Lett. 83, 2030 (1999)
N. García, M. Muñoz, Y.-W. Zhao, Appl. Phys. Lett. 76, 2586 (2000)
J.-E. Wegrowe, T. Wade, X. Hoffer, L. Gravier, J.-M. Bonard, J.-Ph. Ansermet, Phys. Rev. B 67, 104418 (2003)
P.-O. Jubert, R. Allenspach, A. Bischof, Phys. Rev. B 69, 220410 (2004)
M.R. Sullivan, D.A. Boehm, D.A. Ateya, S.Z. Hua, H.D. Chopra, Phys. Rev. B 71, 024412 (2005)
H.D. Chopra, M.R. Sullivan, J.N. Armstrong, S.Z. Hua, Nature Mat. 4, 832 (2005)
N. García, M. Muñoz, V.V. Osipov, E.V. Ponizovskaya, G.G. Qian, I.G. Saveliev, Y.-W. Zhao, J. Magn. Magn. Mater. 240, 92 (2002)
H. Imamura, N. Kobayashi, S. Takahashi, S. Maekawa, Phys. Rev. Lett. 84, 1003 (2000)
Y.-W. Zhao, M. Muñoz, G. Tatara, N. García, J. Magn. Magn. Mater. 223, 169 (2001)
L.R. Tagirov, B.P. Vodopyanov, K.B. Efetov, Phys. Rev. B 63, 104468 (2001)
L.L. Savchenko, A.K. Zvezdin, A.F. Popkov, K.A. Zvezdin, Fiz. Tverd. Tela (St. Petersburg) 43, 1449 (2001) [Phys. Solid State 43, 1509 (2001)]
V.A. Molyneux, V.V. Osipov, E.V. Ponizovskaya, Phys. Rev. B 65, 184425 (2002)
Y. Labaye, L. Berger, J.M.D. Coey, J. Appl. Phys. 91, 5341 (2002)
B.A. Gurney, V.S. Speriosu, J.-P. Nozières, H. Lefakis, D.R. Wilhoit, O.U. Need, Phys. Rev. Lett. 71, 4023 (1993)
B. Dieny, J. Magn. Magn. Mater. 136, 335 (1994)
N. García, Y.-W. Zhao, M. Muñoz, I.G. Saveliev, IEEE Trans. Magn. 36, 2833 (2000)
S.H. Chung, M. Muñoz, N. García, W.F. Egelhoff, R.D. Gomez, Phys. Rev. Lett. 89, 287203 (2002)
A.N. Useinov, R.G. Deminov, L.R. Tagirov, G. Pan, J. Phys.: Condens. Matter 19, 196215 (2007)
P. Bruno, Phys. Rev. Lett. 83, 2425 (1999)
L.R. Tagirov, B.P. Vodopyanov, K.B. Efetov, Phys. Rev. B 65, 214419 (2002)
V.A. Gopar, D. Weinmann, R.A. Jalabert, R.L. Stamps, Phys. Rev. B 69, 014426 (2004)
N. Kazantseva, R. Wieser, U. Nowak, Phys. Rev. Lett. 94, 037206 (2005)
M.B. Stearns, J. Magn. Magn. Mater. 5, 167 (1977); J. Appl. Phys. 73, 6396 (1993)
R. Jansen, J.C. Lodder, Phys. Rev. B 61, 5860 (2000)
B.P. Vodopyanov, L.R. Tagirov, J. Phys.: Condens. Matter 18, 1545 (2006)
T. Valet, A. Fert, Phys. Rev. B 48, 7099 (1993)
A. Fert, I.A. Campbell, J. Phys. F: Metal Phys. 6, 849 (1976)
D.Y. Petrovykh, K.N. Altmann, H. Höchst, M. Laubscher, S. Maat, G.J. Mankey, F.J. Himpsel, Appl. Phys. Lett. 73, 3459 (1998)
K.N. Altmann, N. Gilman, J. Hayoz, R.F. Willis, F.J. Himpsel, Phys. Rev. Lett. 87, 137201 (2001)
J.M.D. Coey, in: Spin Electronics, Springer Lecture Notes in Physics, Vol. 569, edited by M. Ziese, M.J. Thornton (Springer-Verlag 2001), p. 279
E. Hirota, H. Sakakima, K. Inomata, Giant Magneto-Resistance Devices, Springer Series in Surface Sciences, Vol. 40 (Springer-Verlag 2002), p. 28
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Useinov, A., Tagirov, L., Deminov, R. et al. Mean-free path effects in magnetoresistance of ferromagnetic nanocontacts. Eur. Phys. J. B 60, 187–192 (2007). https://doi.org/10.1140/epjb/e2007-00335-8
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DOI: https://doi.org/10.1140/epjb/e2007-00335-8