Magnetoresistance effect element and method for producing the same, and magnetoresistance effect type head, magnetic recording apparatus, and magnetoresistance effect memory element

Abstract

A magnetoresistance effect element includes a free layer, in which a magnetization direction thereof is easily rotated in response to an external magnetic field, a first non-magnetic layer, and a first pinned layer provided on a side opposite to the free layer of the first non-magnetic layer, in which a magnetization direction of the first pinned layer is not easily rotated in response to the external magnetic field. At least one of the first pinned layer and the free layer includes a first metal magnetic film contacting the first non-magnetic layer, and a first oxide magnetic film.

What is claimed is:  
     
         1 . A magnetoresistance effect element comprising: 
 a free layer, wherein a magnetization direction thereof is easily rotated in response to an external magnetic field;    a first non-magnetic layer; and    a first pinned layer provided on a side opposite to the free layer of the first non-magnetic layer, wherein a magnetization direction of the first pinned layer is not easily rotated in response to the external magnetic field,    wherein at least one of the first pinned layer and the free layer includes a first metal magnetic film contacting the first non-magnetic layer, and a first oxide magnetic film.    
     
     
         2 . A magnetoresistance effect element according to  claim 1 , wherein the first pinned layer includes the first metal magnetic film and the first oxide magnetic film.  
     
     
         3 . A magnetoresistance effect element according to  claim 1  further comprising: 
 a second non-magnetic layer provided on a side opposite to the first non-magnetic layer of the free layer; and  
 a second pinned layer provided on a side opposite to the free layer of the second non-magnetic layer, wherein a magnetization direction of the second pinned layer is not easily rotated in response to the external magnetic field.  
 
     
     
         4 . A magnetoresistance effect element according to  claim 1 , wherein the free layer includes the first metal magnetic film and the first oxide magnetic film.  
     
     
         5 . A magnetoresistance effect element according to  claim 2  further comprising: 
 an oxide non-magnetic film provided on a side opposite to the first non-magnetic layer of the free layer, having satisfactory flatness.  
 
     
     
         6 . A magnetoresistance effect element according to  claim 1  further comprising: 
 a pinning layer magnetically coupled to the first oxide magnetic film.  
 
     
     
         7 . A magnetoresistance effect element according to  claim 4 , wherein the free layer further comprises a second metal magnetic film provided on a side opposite to the first metal magnetic film of the first oxide magnetic film.  
     
     
         8 . A magnetoresistance effect element according to  claim 1  further comprising: 
 a pinning layer magnetically coupled to the first pinned layer.  
 
     
     
         9 . A magnetoresistance effect element according to  claim 1 , wherein the first pinned layer further comprises a second metal magnetic film provided on a side opposite to the first metal magnetic film of the first oxide magnetic film.  
     
     
         10 . A magnetoresistance effect element according to  claim 1 , wherein the first pinned layer further comprises: 
 a second metal magnetic film provided on a side opposite to the first metal magnetic film of the first oxide magnetic film;    a third metal magnetic film; and    an exchange-coupling non-magnetic film antiferromagnetically exchange-coupling the second and third metal magnetic films.    
     
     
         11 . A magnetoresistance effect element according to  claim 1 , wherein the first pinned layer further comprises: 
 a non-magnetic film provided on a side opposite to the first metal magnetic film of the first oxide magnetic film; and    a second oxide magnetic film magnetically exchange-coupling the first oxide magnetic film via the non-magnetic films.    
     
     
         12 . A magnetoresistance effect element according to  claim 1 , wherein the first oxide magnetic film comprises Fe.  
     
     
         13 . A magnetoresistance effect element according to  claim 1 , wherein the first oxide magnetic film comprises Fe and X, where X is at least one element selected from Al, Si, B, and N.  
     
     
         14 . A magnetoresistance effect element according to  claim 1 , wherein the first oxide magnetic film comprises MFe 2 O 4  as a major component where M is at least one element selected from Fe, Co, and Ni.  
     
     
         15 . A magnetoresistance effect element according to  claim 1 , wherein the first oxide magnetic film comprises Fe 3 O 4  as a major component.  
     
     
         16 . A magnetoresistance effect element according to  claim 1 , wherein the first oxide magnetic film comprises CoFe 2 O 4  as a major component.  
     
     
         17 . A magnetoresistance effect element according to  claim 6 , wherein the pinning layer comprises P—Mn where P is at least one element selected from Pt, Ni, Pd, Ir, Rh, Ru, and Cr.  
     
     
         18 . A magnetoresistance effect element according to  claim 6 , wherein the pinning layer comprises either α-Fe 2 O 3  or NiO, or both, or includes an α-Fe 2 O 3  film and a NiO film.  
     
     
         19 . A magnetoresistance effect element according to  claim 6 , wherein the pinning layer comprises an (AB) 2 O x  layer where a ratio of a combination of element A and element B to oxygen is equal to 2:x; 2.8<x<32; and where t is defined as:  
         t =( Ra+Ro )/({square root}2·( Rb+Ro ))  (where Ra, Rb, and Ro denote the ion radii of the atoms A, B, and O, respectively)    and t satisfies 0.8<t<0.97.    
     
     
         20 . A magnetoresistance effect element according to  claim 19 , wherein element B of the (AB) 2 O x  layer comprises at least one transition metal, and has Fe as a major component.  
     
     
         21 . A magnetoresistance effect element according to  claim 19 , wherein element of the (AB) 2 O x  layer comprises at least one element selected from rare earth metals.  
     
     
         22 . A magnetoresistance effect element according to  claim 1 , wherein the first oxide magnetic film is an oxide of the first metal magnetic film.  
     
     
         23 . A magnetoresistance effect element according to  claim 22 , wherein the first metal magnetic film comprises a Co—Fe alloy.  
     
     
         24 . A magnetoresistance effect element according to  claim 1 , wherein the free layer comprises a non-magnetic film and two metal magnetic films which are antiferromagnetically exchange-coupled via the non-magnetic film; and the two films have different thicknesses or different levels of saturated magnetization.  
     
     
         25 . A magnetoresistance effect element according to  claim 1 , wherein the magnetoresistance effect element further comprises electrodes provided on the upper and lower sides thereof; and a current flows vertically through the magnetoresistance effect element.  
     
     
         26 . A magnetoresistance effect type head comprising: 
 a magnetoresistance effect element according to  claim 1;  and    a shield.    
     
     
         27 . A magnetoresistance effect type head comprising: 
 a magnetoresistance effect element according to  claim 1;  and    a yoke for introducing a magnetic field into the magnetoresistance effect element.    
     
     
         28 . A magnetic recording apparatus comprising: 
 a magnetoresistance effect type head according to  claim 26;     a servo section for controlling the magnetoresistance effect type head to track a recording medium; and    a signal processing section for processing a signal which the magnetoresistance effect type head records or reproduces onto or from the recording medium.    
     
     
         29 . A magnetoresistance effect memory element comprising: 
 a magnetoresistance effect element according to  claim 1;     an information reading lead line for reading information from the magnetoresistance effect element; and    an information recording lead line for recording the information into the magnetoresistance effect element.    
     
     
         30 . A method for producing a magnetoresistance effect element according to  claim 1 , comprising: 
 a first step for forming the first oxide magnetic film via sputtering using an oxide target.    
     
     
         31 . A method according to  claim 30 , wherein the oxide target comprises Fe 3 O 4 .  
     
     
         32 . A method according to  claim 30 , wherein the first step includes a second step for forming the first oxide magnetic film via sputtering using an inert gas and oxygen gas.  
     
     
         33 . A method according to  claim 31 , wherein the first step includes a second step for forming the first oxide magnetic film via sputtering using an inert gas and oxygen gas.  
     
     
         34 . A method according to  claim 30 , wherein the oxide target comprises CoFe 2 O 4 .  
     
     
         35 . A method for producing a magnetoresistance effect element, comprising: 
 a first step for forming a free layer, a non-magnetic layer, and a metal magnetic film of a pinned layer successively directly on a substrate, or via a layer on the substrate:    a second step for oxidizing a surface of the metal magnetic film of the pinned layer;    a third step for forming an oxide magnetic film on a surface of the metal magnetic film; and    a fourth step for forming a pinning layer on the oxide magnetic film,    wherein a magnetization direction of the free layer is easily rotated in response to an external magnetic field, and a magnetization direction of the pinned layer is not easily rotated in response to an external magnetic field.    
     
     
         36 . A method according to  claim 35 , wherein the second step includes plasma oxidization.  
     
     
         37 . A method according to  claim 35 , wherein the second step includes a step for oxidizing the surface of the metal magnetic film using oxygen radicals generated by an oxygen radical source.  
     
     
         38 . A method according to  claim 35 , wherein the second step includes natural oxidization.  
     
     
         39 . A method according to  claim 35 , wherein the second step includes a step for oxidizing the surface of the metal magnetic film using oxygen ions generated by an oxygen ion source.  
     
     
         40 . A method for producing a magnetoresistance effect element, comprising: 
 a first step for forming a free layer, a non-magnetic layer, and a first metal magnetic film of a pinned layer successively directly on a substrate, or via a layer on the substrate;    a second step for forming an oxide magnetic film of the pinned layer via reactive sputtering;    a third step for forming a second metal magnetic film on a surface of the oxide magnetic film; and    a fourth step for forming a pinning layer on the second magnetic film,    wherein a magnetization direction of the free layer is easily rotated in response to an external magnetic field, and a magnetization direction of the pinned layer is not easily rotated in response to an external magnetic field.