Current perpendicular to the plane reader with improved giant magneto-resistance

Abstract

In some embodiments, a current perpendicular to the plane giant magneto-resistance (CPP GMR) read sensor may include a reference layer and/or a free layer that includes a plurality of sub-layers. For example, at least one of the reference layer or free layer may include a first ferromagnetic sub-layer, a second ferromagnetic sub-layer, and a Heusler alloy layer located between the first ferromagnetic sub-layer and the second ferromagnetic sub-layer. In some embodiments, a CPP GMR read sensor may include a current closed path (CCP) spacer layer between the reference layer and the free layer. The CCP spacer layer may include Ag and Al 2 O 3 . In further embodiments, a CPP GMR read sensor may include a Heusler alloy free layer, a Heusler alloy reference layer, and a CCP spacer layer.

1 . A sensor comprising:
 a free layer;   a nonmagnetic spacer layer; and   a reference layer, wherein at least one of the reference layer and the free layer comprises a first ferromagnetic sub-layer, a Heusler alloy sub-layer, and a second ferromagnetic sub-layer, wherein the Heusler alloy sub-layer is located between the first ferromagnetic sub-layer and the second ferromagnetic sub-layer, and wherein the second ferromagnetic sub-layer is adjacent the nonmagnetic spacer layer.   
     
     
         2 . The sensor of  claim 1 , wherein the Heusler alloy sub-layer comprises X 2 YZ, wherein X comprises an element selected from the group consisting of Co, Ir, Rh, Pt, Cu, and combinations thereof, wherein Y comprises an element selected from the group consisting of V, Cr, Mn, Fe, and combinations thereof, and wherein Z comprises an element selected from the group consisting of Al, Si, Ga, Sn, Ge, and combinations thereof. 
     
     
         3 . The sensor of  claim 2 , wherein the Heusler alloy sub-layer comprises CO 2 MnGe comprising about 15 at. % to about 40 at. % Mn, about 15 at. % to about 40 at. % Ge, and the balance Co. 
     
     
         4 . The sensor of  claim 1 , wherein at least one of the first ferromagnetic sub-layer and the second ferromagnetic sub-layer comprises at least one of CoFe and CoFeB. 
     
     
         5 . The sensor of  claim 1 , wherein the at least one of the reference layer and the free layer further comprises a nonmagnetic metal sub-layer located between the second ferromagnetic sub-layer and the Heusler alloy sub-layer. 
     
     
         6 . The sensor of  claim 1 , wherein the first ferromagnetic sub-layer comprises a thickness of about 1 Å to about 15 Å. 
     
     
         7 . The sensor of  claim 1 , wherein the second ferromagnetic sub-layer comprises a thickness of about 1 Å to about 20 Å. 
     
     
         8 . The sensor of  claim 1 , wherein the nonmagnetic spacer layer comprises a current confined path (CCP) spacer layer. 
     
     
         9 . The sensor of  claim 8 , further comprising a first interlayer between the CCP spacer layer and the free layer and a second interlayer between the CCP spacer layer and the reference layer. 
     
     
         10 . A sensor comprising:
 a free layer comprising a Heusler alloy;   a reference layer comprising a Heusler alloy; and   a current confined path (CCP) spacer layer located between the free layer and the reference layer.   
     
     
         11 . The sensor of  claim 10 , wherein CCP spacer layer comprises a first element selected from the group consisting of Cu, Ag, Au, Co, Fe, Ni, Ta, W, and combinations thereof, and at least one of an oxide, nitride and oxynitride of an element selected from the group consisting of Al, Si, Hf, Mg, Ti, Ta, Mo, W, Nb, Cr, Zr, and combinations thereof. 
     
     
         12 . The sensor of  claim 10 , wherein the CCP spacer layer comprises Ag and Al 2 O 3 . 
     
     
         13 . The sensor of  claim 12 , wherein the CCP spacer layer comprises about 5 at. % to about 15 at. % Ag. 
     
     
         14 . The sensor of  claim 10 , further comprising at least one of a first interlayer between the CCP spacer layer and the free layer and a second interlayer between the CCP spacer layer and the reference layer, and wherein the at least one of the first interlayer and the second interlayer comprises an element selected from the group consisting of Al, Ti, Cu, Mg, Ag, Au, Co, Fe, Ni, and combinations thereof. 
     
     
         15 . The read sensor of  claim 10 , wherein the Heusler alloy comprises X 2 YZ, wherein X comprises an element selected from the group consisting of Co, Ir, Rh, Pt, Cu, and combinations thereof, wherein Y comprises an element selected from the group consisting of V, Cr, Mn, Fe, and combinations thereof, and wherein Z comprises an element selected from the group consisting of Al, Si, Ga, Sn, Ge, and combinations thereof. 
     
     
         16 . A sensor comprising:
 a free layer;   a reference layer; and   a current confined path (CCP) spacer layer located between the free layer and the reference layer, wherein the CCP spacer layer comprises Ag and at least one of an oxide, a nitride and an oxynitride of an element selected from the group consisting of Al, Si, Hf, Mg, Ti, Ta, Mo, W, Nb, Cr, Zr, and combinations thereof.   
     
     
         17 . The read sensor of  claim 16 , wherein the CCP spacer layer comprises Ag and Al 2 O 3 . 
     
     
         18 . The read sensor of  claim 17 , wherein the CCP spacer layer comprises about 5 at. % Ag to about 15 at. % Ag. 
     
     
         19 . The read sensor of  claim 16 , further comprising a first interlayer between the CCP spacer layer and the free layer and a second interlayer between the CCP spacer layer and the reference layer. 
     
     
         20 . The read sensor of  claim 19 , wherein at least one of the first interlayer and the second interlayer comprises an element selected from the group consisting of Al, Ti, Cu, Mg, Ag, Au, Co, Fe, Ni, and combinations thereof.