Spin-valve element having fixed layer containing nano-oxide layer

Abstract

A nonmagnetic material-noncontact layer forming a fixed magnetic layer is formed using CoFe, a nonmagnetic material-contact layer is formed using Co, and an NOL (Nano-Oxide Layer) is provided between the nonmagnetic material-noncontact layer and the nonmagnetic material-contact layer. In addition, the average film thickness of the nonmagnetic material-contact layer is set in the range of 16 to 19 Å. Accordingly, compared to a three-layered structure composed of CoFe, an NOL, and CoFe or a three-layered structure composed of Co, an NOL, and Co, which has been conventionally used, the rate (ΔR/R) of change in resistance and the unidirectional exchange bias magnetic field (Hex*) can both be improved.

1 . A method of manufacturing a magnetic sensor, the method comprising:
 forming an antiferromagnetic layer on a substrate;   forming a fixed magnetic layer;   forming a nonmagnetic interlayer; and   forming a second fixed magnetic layer, the layers being formed in order from the bottom, the formation of the second fixed magnetic layer comprising:
 forming a nonmagnetic noncontact-material layer; 
 oxidizing the nonmagnetic noncontact-material layer; and 
 subsequently forming a nonmagnetic contact-material layer. 
   
     
     
         2 . The method according to  claim 1 , further comprising forming a Cr layer on the nonmagnetic material-noncontact layer prior to oxidizing the nonmagnetic noncontact-material layer. 
     
     
         3 . The method of  claim 1 , wherein only a portion of the surface of the nonmagnetic material-noncontact layer is oxidized. 
     
     
         4 . The method of  claim 1 , wherein only portions of the Cr layer and the nonmagnetic material-noncontact layer are oxidized. 
     
     
         5 . The method of  claim 1 , wherein the NOL is formed by natural oxidation. 
     
     
         6 . The method of  claim 1 , wherein the oxidation results in intermittent portions dispersedly formed in the surface of the nonmagnetic material-noncontact layer. 
     
     
         7 . The method of  claim 2 , wherein the oxidation results in intermittent portions in the Cr layer and the nonmagnetic material-noncontact layer.