Magnetoresistive element, manufacturing method thereof and magnetic sensor

Abstract

A magnetoresistive element has a magnetization free layer whose magnetization direction changes in an external magnetic field; a magnetization pinned layer whose magnetization direction is pinned in the external magnetic field; and a barrier layer that is positioned between the magnetization free layer and the magnetization pinned layer and that exhibits a magnetoresistive effect. The barrier layer is an oxide of an alloy that includes Mg and Al, and the barrier layer includes a crystalline region and a non-crystalline region.

1 - 11 . (canceled) 
     
     
         12 . A method of manufacturing a magnetoresistive element comprising the steps of:
 forming either a magnetization free layer whose magnetization direction changes depending on an external magnetic field or a metal layer that is to be a magnetization pinned layer whose magnetization direction is pinned against the external magnetic field, wherein either one of the magnetization free layer and the metal layer includes a CoFe layer and the CoFe layer is a top layer of said either one of the layers;   forming a film that includes Mg and Al atop said either one of the layers;   oxidizing the film in order to form a barrier layer that has a magnetoresistive effect and that includes a crystalline region and a non-crystalline region;   forming a remaining one of the magnetization free layer and the metal layer atop the barrier layer; and   pinning the magnetization direction of the metal layer in order to form the magnetization pinned layer,   wherein said either one of the layers is amorphous, and a boundary portion between the CoFe layer and the barrier layer is crystallized by annealing.   
     
     
         13 . The method according to  claim 12 , wherein the remaining one includes another CoFe layer, and the remaining one is formed such that said another CoFe layer is adjacent to the film,
 wherein the remaining one is amorphous, and a boundary portion between said another CoFe layer and the barrier layer is crystallized by annealing.   
     
     
         14 . The method according to  claim 12 , wherein the film includes a Mg film and a MgAl film. 
     
     
         15 . A magnetoresistive element comprising:
 a magnetization free layer whose magnetization direction changes depending on an external magnetic field;   a magnetization pinned layer whose magnetization direction is pinned against the external magnetic field; and   a barrier layer that is positioned between the magnetization free layer and the magnetization pinned layer and that exhibits a magnetoresistive effect;   wherein the barrier layer is an oxide of a film that includes Mg and Al, and includes a crystalline region and a non-crystalline region, and   at least either the magnetization free layer or the magnetization pinned layer includes a metal layer that is adjacent to the barrier layer, wherein the metal layer contains at least either Co or Fe.   
     
     
         16 . The magnetoresistive element according to  claim 15 , wherein the metal layer is a CoFe layer. 
     
     
         17 . The magnetoresistive element according to  claim 16 , wherein a boundary portion between the metal layer and the barrier layer is crystalline. 
     
     
         18 . A magnetic sensor comprising the magnetoresistive element according to  claim 15 .