Magneto-resistive element magnetic head, and magnetic recording and reproduction apparatus

Abstract

A magneto-resistive element includes a magnetic substrate; a magnetic layer; and a non-magnetic layer provided between the magnetic substrate and the magnetic layer.

What is claimed is:  
     
         1 . A magneto-resistive element, comprising: 
 a magnetic substrate;    a magnetic layer; and    a non-magnetic layer provided between the magnetic substrate and the magnetic layer.    
     
     
         2 . A magneto-resistive element according to  claim 1 , wherein a relative angle between a magnetization direction of the magnetic substrate and a magnetization direction of the magnetic layer changes in accordance with a change in an external magnetic field.  
     
     
         3 . A magneto-resistive element according to  claim 1 , wherein: 
 the magnetic substrate includes a free layer in which magnetization rotation with respect to an external magnetic field is possible, and    the magnetic layer includes a fixed layer in which magnetization rotation with respect to the external magnetic field is more difficult to occur than in the free layer.    
     
     
         4 . A magneto-resistive element according to  claim 1 , further comprising a hard magnetic layer with a large coercive force provided so as to face the magnetic substrate with the magnetic layer interposed therebetween.  
     
     
         5 . A magneto-resistive element according to  claim 1 , further comprising an anti-ferromagnetic layer provided so as to face the magnetic substrate with the magnetic layer interposed therebetween.  
     
     
         6 . A magneto-resistive element according to  claim 5 , further comprising a synthetic anti-ferromagnetic layer provided so as to face the magnetic substrate with the magnetic layer interposed therebetween, the synthetic anti-ferromagnetic layer being magnetically coupled with the anti-ferromagnetic layer.  
     
     
         7 . A magneto-resistive element according to  claim 1 , further comprising a soft magnetic layer with a high saturation magnetic flux density provided between the magnetic substrate and the non-magnetic layer.  
     
     
         8 . A magneto-resistive element according to  claim 1 , further comprising an anti-ferromagnetic layer provided between the magnetic substrate and the non-magnetic layer.  
     
     
         9 . A magneto-resistive element according to  claim 1 , wherein the magnetic substrate contains ferrite.  
     
     
         10 . A magneto-resistive element according to  claim 1 , wherein the magnetic substrate contains an oxide.  
     
     
         11 . A magneto-resistive element according to  claim 1 , wherein the magnetic substrate contains a single crystalline oxide.  
     
     
         12 . A magneto-resistive element according to  claim 1 , wherein the magnetic layer contains magnetite.  
     
     
         13 . A magneto-resistive element according to  claim 1 , wherein the magnetic layer contains at least one element selected from the group consisting of O, N. P, C and B.  
     
     
         14 . A magneto-resistive element according to  claim 1 , wherein the non-magnetic layer includes a tunnel layer.  
     
     
         15 . A magneto-resistive element according to  claim 1 , wherein the non-magnetic layer includes a metal non-magnetic layer.  
     
     
         16 . A magneto-resistive element, comprising: 
 a magnetic substrate;    a first magnetic layer;    a second magnetic layer provided so as to face the magnetic substrate with the first magnetic layer interposed therebetween; and    a first non-magnetic layer provided between the first magnetic layer and the second magnetic layer.    
     
     
         17 . A magneto-resistive element according to  claim 16 , wherein a relative angle between a magnetization direction of the first magnetic layer and a magnetization direction of the second magnetic layer changes in accordance with a change in an external magnetic field.  
     
     
         18 . A magneto-resistive element according to  claim 16 , wherein the magnetic substrate and the first magnetic layer are magnetically coupled with each other.  
     
     
         19 . A magneto-resistive element according to  claim 16 , wherein the magnetic substrate and the first magnetic layer are coupled with each other by ferromagnetic coupling by which a magnetization direction of the magnetic substrate and a magnetization direction of the first magnetic layer are parallel to each other.  
     
     
         20 . A magneto-resistive element according to  claim 16 , wherein the magnetic substrate and the first magnetic layer are coupled with each other by ferromagnetic coupling by which a magnetization direction of the magnetic substrate and a magnetization direction of the first magnetic layer are anti-parallel to each other.  
     
     
         21 . A magneto-resistive element according to  claim 16 , wherein the magnetic substrate and the first magnetic layer are coupled with each other by static magnetic coupling.  
     
     
         22 . A magneto-resistive element according to  claim 16 , further comprising an underlying layer provided between the magnetic substrate and the first magnetic layer.  
     
     
         23 . A magneto-resistive element according to  claim 22 , wherein the underlying layer includes a second non-magnetic layer.  
     
     
         24 . A magneto-resistive element according to  claim 22 , wherein the underlying layer includes an anti-ferromagnetic layer.  
     
     
         25 . A magneto-resistive element according to  claim 22 , wherein the underlying layer has a thickness in the range of 0.5 nm to 50 nm including 0.5 nm and 50 nm.  
     
     
         26 . A magneto-resistive element according to  claim 16 , wherein: 
 the first magnetic layer includes a free layer in which magnetization rotation with respect to an external magnetic field is possible, and    the second magnetic layer includes a fixed layer in which magnetization rotation with respect to the external magnetic field is more difficult to occur than in the free layer.    
     
     
         27 . A magneto-resistive element according to  claim 16 , further comprising a hard magnetic layer with a large coercive force provided so as to face the magnetic substrate with the second magnetic layer interposed therebetween.  
     
     
         28 . A magneto-resistive element according to  claim 16 , further comprising an anti-ferromagnetic layer provided so as to face the magnetic substrate with the second magnetic layer interposed therebetween.  
     
     
         29 . A magneto-resistive element according to  claim 28 , further comprising a synthetic anti-ferromagnetic layer provided so as to face the magnetic substrate with the second magnetic layer interposed therebetween, the synthetic anti-ferromagnetic layer being magnetically coupled with the anti-ferromagnetic layer.  
     
     
         30 . A magneto-resistive element according to  claim 16 , further comprising a soft magnetic layer with a high saturation magnetic flux density provided between the magnetic substrate and the first magnetic layer.  
     
     
         31 . A magneto-resistive element according to  claim 16 , wherein the magnetic substrate contains ferrite.  
     
     
         32 . A magneto-resistive element according to  claim 16 , wherein the magnetic substrate contains an oxide.  
     
     
         33 . A magneto-resistive element according to  claim 16 , wherein the magnetic substrate contains a single crystalline oxide.  
     
     
         34 . A magneto-resistive element according to  claim 16 , wherein the first magnetic layer contains magnetite.  
     
     
         35 . A magneto-resistive element according to  claim 16 , wherein the first magnetic layer contains at least one element selected from the group consisting of O, N. P, C and B.  
     
     
         36 . A magneto-resistive element according to  claim 16 , wherein the first non-magnetic layer includes a tunnel layer.  
     
     
         37 . A magneto-resistive element according to  claim 16 , wherein the first non-magnetic layer includes a metal non-magnetic layer.  
     
     
         38 . A magneto-resistive element according to  claim 16 , further comprising a flux guide provided so as to face the magnetic substrate with the second magnetic layer interposed therebetween.  
     
     
         39 . A magneto-resistive element according to  claim 38 , further comprising a non-magnetic conductive layer provided so as to face the magnetic substrate with the flux guide interposed therebetween.  
     
     
         40 . A magneto-resistive element according to  claim 16 , wherein the first magnetic layer includes a magnetic layer with a high spin polarization.  
     
     
         41 . A magneto-resistive element according to  claim 40 , wherein the first magnetic layer further includes a non-magnetic layer for anti-ferromagnetic exchange coupling.  
     
     
         42 . A magneto-resistive element according to  claim 41 , wherein the first magnetic layer further includes a magnetic layer for anti-ferromagnetic exchange coupling provided so as to face the magnetic layer with a high spin polarization with the nonmagnetic layer for anti-ferromagnetic exchange coupling interposed therebetween.  
     
     
         43 . A magneto-resistive element according to  claim 42 , wherein the first magnetic layer further includes an anti-ferromagnetic layer provided so as to face the non-magnetic layer for anti-ferromagnetic exchange coupling with the magnetic layer for anti-ferromagnetic exchange coupling interposed therebetween.  
     
     
         44 . A magnetic head, comprising: 
 a magneto-resistive element including: 
 a magnetic substrate,  
 a magnetic layer, and  
 a nonmagnetic layer provided between the magnetic substrate and the magnetic layer; and  
   a yoke,    wherein: 
 the yoke has a magnetic gap formed of a non-magnetic material, and  
 the magnetic substrate acts as a portion of the yoke.  
   
     
     
         45 . A magnetic head according to  claim 44 , wherein the yoke includes a magnetic member having a saturation magnetic flux density higher than a saturation magnetic flux density of the magnetic substrate at least in the vicinity of the magnetic gap, the magnetic head further comprising an electromagnetic coil wound around the yoke.  
     
     
         46 . A magnetic head, comprising: 
 a magneto-resistive element including: 
 a magnetic substrate,  
 a first magnetic layer,  
 a second magnetic layer provided so as to face the magnetic substrate with the first magnetic layer interposed therebetween, and  
 a first non-magnetic layer provided between the first magnetic layer and the second magnetic layer; and  
   a yoke,    wherein: 
 the yoke has a magnetic gap formed of a non-magnetic material, and  
 the magnetic substrate acts as a portion of the yoke.  
   
     
     
         47 . A magnetic head according to  claim 46 , wherein the yoke includes a magnetic member having a saturation magnetic flux density higher than a saturation magnetic flux density of the magnetic substrate at least in the vicinity of the magnetic gap, the magnetic head further comprising an electromagnetic coil wound around the yoke.  
     
     
         48 . A magnetic recording and reproduction apparatus, comprising: 
 a magnetic head according to  claim 44  for reproducing data from a recording medium so as to generate a signal and for recording data represented by a signal on the recording medium;    an arm for mounting the magnetic head;    a driving section for driving the arm; and    a signal processing section for processing the signal,    wherein the recording medium is surface-treated with a DLC film.    
     
     
         49 . A magnetic recording and reproduction apparatus according to  claim 48 , wherein the yoke has a surface facing the recording medium, and the surface is surface-treated with a DLC film.  
     
     
         50 . A magnetic recording and reproduction apparatus, comprising: 
 a magnetic head according to  claim 46  for reproducing data from a recording medium so as to generate a signal and for recording data represented by a signal on the recording medium;    an arm for mounting the magnetic head;    a driving section for driving the arm; and    a signal processing section for processing the signal,    wherein the recording medium is surface-treated with a DLC film.    
     
     
         51 . A magnetic recording and reproduction apparatus according to claim SO, wherein the yoke has a surface facing the recording medium, and the surface is surface-treated with a DLC film.  
     
     
         52 . A magnetic recording and reproduction apparatus, comprising: 
 a magnetic head according to claim  44 ;    a rotatable drum for mounting the magnetic head on an external circumferential surface thereof; and    a tape guiding mechanism for guiding the magnetic tape to the rotatable drum so as to place the magnetic tape into contact with the external circumferential surface,    wherein the magnetic head records data on and reproduce data from the magnetic tape.    
     
     
         53 . A magnetic recording and reproduction apparatus according to  claim 52 , wherein the yoke has a surf ace facing the magnetic tape, and the surface is surface-treated with a DLC film.  
     
     
         54 . A magnetic recording and reproduction apparatus, comprising: 
 a magnetic head according to claim  46 ;    a rotatable drum for mounting the magnetic head on an external circumferential surface thereof; and    a tape guiding mechanism for guiding the magnetic tape to the rotatable drum so as to place the magnetic tape into contact with the external circumferential surface,    wherein the magnetic head records data on and reproduce data from the magnetic tape.    
     
     
         55 . A magnetic recording and reproduction apparatus according to  claim 54 , wherein the yoke has a surface facing the magnetic tape, and the surface is surface-treated with a DLC film.