Abstract
Spin valve magnetic sensors have been the most popular choice for high-area-density magnetic read heads. How to enhance the value of magnetoresistance in basic spin valves is an important issue. The question of surface scattering in spin valve has recently become a subject of great interest. It is now generally appreciated that the creation of specularly reflecting surfaces will enhance the giant magnetoresistance (GMR) in spin valves, as the mean free path will increase. In this work, the thin films were prepared by direct current magnetron sputtering system on the Si substrates. An orientation filed of 300 Oe was applied during the deposition of samples. The magnetic and electric properties of these films were characterized by magneto-optic Kerr effect (MOKE) magnetometry and four-point probe respectively. Their microstructures were characterized by X-ray diffractometer. And the surface roughness of the films were measured by atomic force microscopy (AFM). We created the interface of nano-oxide/ferromagnetic by oxidizing the metal films. And we have successfully enhanced the MR ratio of [Co/Cu/Co/FeMn] spin valve from 4.84% to 6.53% with adding the oxide/ferromagnetic interface. After annealing at 150℃, the MR ratio of the spin valve with oxide achieved 7.21%. Because of the defect in the oxide/ferromagnetic interface decreased, the effect of specular reflection increased. Then the MR ratio has marvelous enhancement.