Study an magnetoresistance and stability for [Py/Cu/Co/Cu]N spin valve multilayered films

The spin valve [NiFe/Cu/Co/Cu] multilayers were prepared by using electron beam method. The influences of the thickness of magnetic and non-magnetic layers preparation process on the magnetoresistance (MR) were studied. We also investigated the stability of MR and how to reduce the center field Ho, which is the center magnetic field of the linear region in the MR-H curve. Using fairly optimum preparing technology, we have deposited many samples with low center field Ho in the range 10-20 Oe, the MR merit is larger than 0.2%/Oe. The variation of the MR in this linear region is reversible during repeatedly magnetizing. The change of MR is smaller than 1% for several samples after aging one year in a dry air chamber and room temperature