Magnetoresistance effect device and method of production of the same

Abstract

A magnetoresistance effect device including a multilayer structure having a pair of ferromagnetic layers and a barrier layer positioned between them, wherein at least one ferromagnetic layer has at least the part contacting the barrier layer made amorphous and the barrier layer is an MgO layer having a highly oriented texture structure.

1 . A magnetoresistance effect device including a multilayer structure comprised of a pair of ferromagnetic layers and a barrier layer positioned between them, wherein 
 at least a part of at least one of said ferromagnetic layers contacting said barrier layer is amorphous, and    said barrier layer is an MgO layer having a single structure.    
     
     
         2 . A magnetoresistance effect device including a multilayer structure comprised of a pair of ferromagnetic layers and a barrier layer positioned between them, wherein 
 at least a part of at least one of said ferromagnetic layers contacting said barrier layer is amorphous, and    said barrier layer is an MgO layer having a highly oriented fiber-texture structure.    
     
     
         3 . The magnetoresistance effect device as set forth in  claim 1 , wherein said MgO layer is a single crystal layer formed by a sputtering method.  
     
     
         4 . The magnetoresistance effect device as set forth in  claim 1 , wherein said MgO layer is a highly oriented fiber-texture layer formed by a sputtering method.  
     
     
         5 . The magnetoresistance effect device as set forth in  claim 3 , wherein said MgO layer is a single crystal layer formed using an MgO target and a sputtering method.  
     
     
         6 . The magnetoresistance effect device as set forth in  claim 4 , wherein said MgO layer is a a highly oriented fiber-texture layer formed using an MgO target and a sputtering method.  
     
     
         7 . The magnetoresistance effect device as set forth in  claim 1 , wherein said ferromagnetic layers are CoFeB layers.  
     
     
         8 . The magnetoresistance effect device as set forth in  claim 2 , wherein said ferromagnetic layers are CoFeB layers.  
     
     
         9 . A method of production of a magnetoresistance effect device including a multilayer structure comprised of a pair of ferromagnetic layers and a barrier layer positioned between them, comprising: 
 forming at least one ferromagnetic layer so that at least a part contacting the barrier layer is amorphous and forming said barrier layer having a single crystal structure by using a sputtering method.    
     
     
         10 . A method of production of a magnetoresistance effect device including a multilayer structure comprised of a pair of ferromagnetic layers and a barrier layer positioned between them, comprising: 
 forming at least one ferromagnetic layer so that at least a part contacting the barrier layer is amorphous and forming said barrier layer having a highly-oriented fiber-texture structure by using a sputtering method.    
     
     
         11 . A method of production of a magnetoresistance effect device as set forth in  claim 9 , further comprising forming said MgO layer by a sputtering method using an MgO target.  
     
     
         12 . A method of production of a magnetoresistance effect device as set forth in  claim 10 , further comprising forming said MgO layer by a sputtering method using an MgO target.