Magnetoresistive element

Abstract

A magnetoresistive element includes a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential, a second magnetic layer, a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer, and a nonmagnetic cap layer which contacts the second surface of the first magnetic layer and is formed from an alloy of a first metal material and a second metal material, the first metal material having a second standard electrode potential lower than the first standard electrode potential, the second metal material having a third standard electrode potential higher than the first standard electrode potential.

1 . A magnetoresistive element comprising: 
 a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential;    a second magnetic layer;    a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer; and    a nonmagnetic cap layer which contacts the second surface of the first magnetic layer and is formed from an alloy of a first metal material and a second metal material, the first metal material having a second standard electrode potential lower than the first standard electrode potential, the second metal material having a third standard electrode potential higher than the first standard electrode potential.    
   
   
       2 . The element according to  claim 1 , wherein a fourth standard electrode potential of the nonmagnetic cap layer is not less than −0.2 V with respect to the first standard electrode potential and is not more than +0.8 V with respect to the first standard electrode potential.  
   
   
       3 . The element according to  claim 2 , wherein the fourth standard electrode potential is calculated from a weighted average of the second standard electrode potential and the third standard electrode potential.  
   
   
       4 . The element according to  claim 1 , wherein the first metal material contains an element selected from the group consisting of Ti, V, Cr, Mn, Zn, Zr, Nb, Hf, Ta, Fe, and Co, and 
 the second metal material contains an element selected from the group consisting of Co, Ni, Cu, Mo, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, and Au.    
   
   
       5 . A magnetoresistive element comprising: 
 a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential;    a second magnetic layer;    a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer;    a nonmagnetic cap layer which is arranged on a side of the second surface of the first magnetic layer and is formed from an alloy of a first metal material and a second metal material, the first metal material having a second standard electrode potential lower than the first standard electrode potential, the second metal material having a third standard electrode potential higher than the first standard electrode potential; and    a diffusion suppressing layer which suppresses diffusion from the nonmagnetic cap layer to the first magnetic layer and is provided between the nonmagnetic cap layer and the first magnetic layer, the diffusion suppressing layer containing one of a metal oxide, a metal nitride, and a metal oxynitride.    
   
   
       6 . The element according to  claim 5 , wherein the diffusion suppressing layer contains one of an oxide, a nitride, and an oxynitride of an element containing an element selected from the group consisting of Al, Mg, B, Ti, Zr, Hf, and Ta.  
   
   
       7 . The element according to  claim 5 , wherein a fourth standard electrode potential of the nonmagnetic cap layer is not less than −0.2 V with respect to the first standard electrode potential and is not more than +0.8 V with respect to the first standard electrode potential.  
   
   
       8 . The element according to  claim 7 , wherein the fourth standard electrode potential is calculated from a weighted average of the second standard electrode potential and the third standard electrode potential.  
   
   
       9 . The element according to  claim 5 , wherein 
 the first metal material contains an element selected from the group consisting of Ti, V, Cr, Mn, Zn, Zr, Nb, Hf, Ta, Fe, and Co, and    the second metal material contains an element selected from the group consisting of Co, Ni, Cu, Mo, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, and Au.    
   
   
       10 . A magnetoresistive element comprising: 
 a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential;    a second magnetic layer;    a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer; and    a nonmagnetic cap layer which contacts the second surface of the first magnetic layer and is formed from an alloy of a magnetic material and a metal material, the metal material having a second standard electrode potential lower than the first standard electrode potential.    
   
   
       11 . The element according to  claim 10 , wherein 
 the magnetic material contains an element selected from the group consisting of Co, Fe, and Ni, and    the metal material contains an element selected from the group consisting of Ti, V, Cr, Mn, Zn, Zr, Nb, Hf, and Ta.    
   
   
       12 . A magnetoresistive element comprising: 
 a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential;    a second magnetic layer;    a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer;    a nonmagnetic cap layer which is arranged on a side of the second surface of the first magnetic layer and is formed from an alloy of a magnetic material and a metal material, the metal material having a second standard electrode potential lower than the first standard electrode potential; and    a diffusion suppressing layer which suppresses diffusion from the nonmagnetic cap layer to the first magnetic layer and is provided between the nonmagnetic cap layer and the first magnetic layer, the diffusion suppressing layer containing one of a metal oxide, a metal nitride, and a metal oxynitride.    
   
   
       13 . The element according to  claim 12 , wherein the diffusion suppressing layer contains one of an oxide, a nitride, and an oxynitride of an element containing an element selected from the group consisting of Al, Mg, B, Ti, Zr, Hf, and Ta.  
   
   
       14 . The element according to  claim 12 , wherein 
 the magnetic material contains an element selected from the group consisting of Co, Fe, and Ni, and    the metal material contains an element selected from the group consisting of Ti, V, Cr, Mn, Zn, Zr, Nb, Hf, and Ta.    
   
   
       15 . A magnetic random access memory comprising: 
 a magnetoresistive element as a memory element,    the magnetoresistive element comprising:    a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential;    a second magnetic layer;    a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer; and    a nonmagnetic cap layer which contacts the second surface of the first magnetic layer and is formed from an alloy of a first metal material and a second metal material, the first metal material having a second standard electrode potential lower than the first standard electrode potential, the second metal material having a third standard electrode potential higher than the first standard electrode potential.    
   
   
       16 . A magnetic random access memory comprising: 
 a magnetoresistive element as a memory element,    the magnetoresistive element comprising:    a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential;    a second magnetic layer;    a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer;    a nonmagnetic cap layer which is arranged on a side of the second surface of the first magnetic layer and is formed from an alloy of a first metal material and a second metal material, the first metal material having a second standard electrode potential lower than the first standard electrode potential, the second metal material having a third standard electrode potential higher than the first standard electrode potential; and    a diffusion suppressing layer which suppresses diffusion from the nonmagnetic cap layer to the first magnetic layer and is provided between the nonmagnetic cap layer and the first magnetic layer, the diffusion suppressing layer containing one of a metal oxide, a metal nitride, and a metal oxynitride.    
   
   
       17 . A magnetic random access memory comprising: 
 a magnetoresistive element as a memory element,    the magnetoresistive element comprising:    a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential;    a second magnetic layer;    a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer; and    a nonmagnetic cap layer which contacts the second surface of the first magnetic layer and is formed from an alloy of a magnetic material and a metal material, the metal material having a second standard electrode potential lower than the first standard electrode potential.    
   
   
       18 . A magnetic random access memory comprising: 
 a magnetoresistive element as a memory element, the magnetoresistive element comprising:    a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential;    a second magnetic layer;    a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer;    a nonmagnetic cap layer which is arranged on a side of the second surface of the first magnetic layer and is formed from an alloy of a magnetic material and a metal material, the metal material having a second standard electrode potential lower than the first standard electrode potential; and    a diffusion suppressing layer which suppresses diffusion from the nonmagnetic cap layer to the first magnetic layer and is provided between the nonmagnetic cap layer and the first magnetic layer, the diffusion suppressing layer containing one of a metal oxide, a metal nitride, and a metal oxynitride.