Europhys. Lett.
Volume 68, Number 5, December 2004
Page(s) 706 - 712
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 05 November 2004
Europhys. Lett., 68 (5), pp. 706-712 (2004)
DOI: 10.1209/epl/i2004-10270-x

Analysis of the magnetotransport channels in tunnel junctions with amorphous $\chem{CoFeB}$

T. Dimopoulos1, G. Gieres1, J. Wecker1, Y. Luo2 and K. Samwer2

1  Siemens AG, Corporate Technology CT-MM1 Paul-Gossen-Str. 100, 91052, Erlangen, Germany
2  I. Physikalisches Institut, University of Göttingen Tammannstr. 1, 37077, Göttingen, Germany

received 1 June 2004; accepted in final form 12 October 2004
published online 5 November 2004

This work concerns the temperature and bias dependence of the magnetotransport properties of $\chem{Al}$ oxide-based tunnel junctions with an amorphous $\chem{Co_{60}Fe_{20}B_{20}}$ soft ferromagnetic electrode and $\chem{CoFe_{10}}$-based polycrystalline hard electrode. The junctions present high tunnel magnetoresistance of $\sim 50$% at room temperature and $\sim 71$% at 5 $\un{K}$. A model that takes magnon-assisted inelastic tunneling into account fits satisfactorily the parallel (P) and antiparallel (AP) conductance as a function of temperature. The extracted fitting parameters are then used to reproduce the low-bias anomaly of the P and AP conductance at low temperature.

73.40.Gk - Tunneling.
73.40.Rw - Metal-insulator-metal structures.
75.47.De - Giant magnetoresistance.

© EDP Sciences 2004