https://doi.org/10.1140/epjb/e2003-00056-0
Analytical result of the effect of spin scattering and impurity-assistance on magnetoresistance in doped magnetic tunneling junctions
1
Department of Physics, Nanjing Normal University, Nanjing
210097, PR China
2
National Laboratory of Solid State Microstructures and Department of
Physics, Nanjing University, Nanjing 210093, PR China
Corresponding author: a yctao12@163.com
Received:
13
January
2002
Revised:
30
November
2002
Published online:
6
March
2003
An extended tunneling Hamiltonian method is proposed to study the temperature-dependent tunneling magnetoresistance (TMR) in doped magnetic tunnel junctions. It is found that for nonmagnetic dopants (Si), impurity-assisted tunneling is mainly elastic, giving rise to a weak spin polarization, thereby reduces the overall TMR, while for magnetic ions (Ni), the collective excitation of local spins in δ-doped magnetic layer contributes to the severe drop of TMR and the behavior of the variation of TMR with temperature different from that for Si-doping. The theoretical results can reproduce the main characteristic features of experiments.
PACS: 75.70.Pa – Giant magnetoresistance / 75.30.Ds – Spin waves / 73.23.Hk – Coulomb blockade; single-electron tunneling
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003
