Ferromagnetic tunnel junctions with high MR and low resistance.-area product

Spin tunnel Junctions with junction area between 50 and 10(4) mu m(2) were fabricated. A,structure of glass/Ta 35 angstrom/NiFe 20 angstrom/IrMn 70 angstrom/CoFe 30 angstrom/Al2O3 15 angstrom/CoFe 50 angstrom/NiFe 45 angstrom/Ta 120 angstrom was used in the Junctions. The junctions have a max MR ratio of 26.17% and a low 2 resistance-area product of 1.22 k Omega center dot mu m(2). The effective barrier height is 1.04eV and the effective barrier thickness is 9.97 angstrom. The max tunneling magnetoresistance (TMR) values is obtained by an N-2 protecting anneal at 300 degrees C for 3 hours applying an external field of 3000 Oe. The as-deposited junctions show a peak-shape tunneling effect. And the peak-shape effect is weaker by increasing the temperature and the time of anneal. The ferromagnetic tunnel junctions with high MR and low resistance-area product are suitable for the applications of magnetic random access memory (MRAM) and magnetic read head.