Ferromagnetically coupled magnetic recording media

Abstract

A ferromagnetically coupled magnetic recording medium having a first ferromagnetic layer, a second ferromagnetic layer, and a ferromagnetic coupling layer to ferromagnetically couple the first ferromagnetic layer to the second ferromagnetic layer is used as stable magnetic media with high MrT in high density recording hard drives. The first ferromagnetic layer is the stabilization layer and the second ferromagnetic layer is the main recording layer. The ferromagnetic coupling layer comprises a conductive material having a thickness which produces ferromagnetic coupling between said first ferromagnetic layer and said second ferromagnetic layer via the RKKY interaction.

1 . A magnetic recording medium, comprising; 
 a first ferromagnetic layer;    a second ferromagnetic layer; and    a ferromagnetic coupling layer to ferromagnetically couple said first ferromagnetic layer to said second ferromagnetic layer.    
     
     
         2 . The magnetic recording medium of  claim 1  wherein said ferromagnetic coupling layer further comprises: 
 a conductive material    a thickness which produces ferromagnetic coupling between said first ferromagnetic layer and said second ferromagnetic layer via the RKKY interaction.    
     
     
         3 . The magnetic recording medium of  claim 2  wherein said conductive material is selected from the group consisting of Ru, Rh, Ir, Cr, Cu, Re, V, and alloys made of these elements.  
     
     
         4 . The magnetic recording medium of  claim 1:   wherein said first ferromagnetic layers is made of a Co-based alloy;    wherein said second ferromagnetic layer is made of a Co-based alloy; and    wherein said ferromagnetic coupling layer is Ru and has a thickness range selected from the group comprising of 0 to 2 angstroms, 11 angstroms to 17 angstroms, and 25 angstroms to 31 angstroms.    
     
     
         5 . The magnetic recording medium of  claim 1  wherein said ferromagnetic coupling layer further comprises a non-magnetic conductive layer that is ferromagnetically polarized in the presence of said first ferromagnetic layer and said second ferromagnetic layer.  
     
     
         6 . The magnetic recording medium of  claim 5  wherein said ferromagnetic coupling layer is made of a material selected from the group consisting of Pt, Pd, Pt-alloys, and Pd-alloys.  
     
     
         7 . The magnetic recording medium of  claim 6  wherein said ferromagnetic coupling layer has a thickness less than 6 nanometers.  
     
     
         8 . The magnetic recording medium of  claim 1  wherein said ferromagnetic coupling layer further comprises a weekly ferromagnetic layer that provides direct exchange interaction coupling between said first ferromagnetic layer and said second ferromagnetic layer.  
     
     
         9 . The magnetic recording medium of  claim 8  wherein said ferromagnetic coupling layer is made of a material selected from the group consisting of Co, Ni, Fe and alloys thereof.  
     
     
         10 . The magnetic recording medium of  claim 8  wherein said ferromagnetic coupling layer has a magnetization less than 300 emu/cm 3 .  
     
     
         11 . The magnetic recording medium of  claim 1  wherein said first ferromagnetic layer and said second ferromagnetic layer are selected from the group consisting of alloys containing Co and Cr, and alloys containing CoCr with one or more added elements selected from the group consisting of Pt, Ta, B, Mo, Ru, Si, Ge, Nb, Fe and Ni.  
     
     
         12 . The magnetic recording medium of  claim 1  wherein said first ferromagnetic layer has a magnetocrystalline anisotropy perpendicular to a film plane and said second ferromagnetic layer has a magnetocrystalline anisotropy perpendicular to a film plane.  
     
     
         13 . The magnetic recording medium of  claim 1  wherein said first ferromagnetic layer has a magnetocrystalline anisotropy parallel to a film plane and said second ferromagnetic layer has a magnetocrystalline anisotropy parallel to a film plane.  
     
     
         14 . The magnetic recording medium of  claim 1  wherein said first ferromagnetic layer has a magnetocrystalline anisotropy parallel to a film plane and said second ferromagnetic layer has a magnetocrystalline anisotropy perpendicular to a film plane.  
     
     
         15 . The magnetic recording medium of  claim 1  wherein said first ferromagnetic layer has a magnetocrystalline anisotropy perpendicular to a film plane and said second ferromagnetic layer has a magnetocrystalline anisotropy parallel to a film plane.  
     
     
         16 . The magnetic recording medium of  claim 13  wherein said first ferromagnetic layer and said second ferromagnetic layer comprises at least one oxide material, said oxide material further comprising an element selected from the group consisting of Si, Al, Ti, Hf, W, Mg, Nb, Fe, B, V, Mn, Ge, Mo, Ru, Rh, Re, Pt, Zr, Y, Cr, Sm, Co, Ni and Ta.  
     
     
         17 . The magnetic recording medium of  claim 13  wherein said first ferromagnetic layer and said second ferromagnetic layer comprises CoCrPt and at least one compound selected from the group consisting of TiO 2 , Al 2 O 3 , MgO, WO 3 , Cr 2 O 3 , Nb 2 O 5 , ZrO 2 , Ta 2 O 5 , MoO 3 , Y 2 O 3 , Sm 2 O 3 , CoO, and SiO 2 .  
     
     
         18 . A magnetic recording medium, comprising; 
 a first ferromagnetic layer;    a first interface layer;    a ferromagnetic coupling layer;    a second interface layer;    a second ferromagnetic layer; and    wherein said ferromagnetic coupling layer is used to ferromagnetically couple said first ferromagnetic layer and said second ferromagnetic layer.    
     
     
         19 . The magnetic recording medium of  claim 18  wherein said first interface layer and said second interface layer have magnetic moments with magnetic saturations greater than 300 emu/cm 3 .  
     
     
         20 . The magnetic recording medium of  claim 18  wherein said first interface layer and said second interface layer are made from a material selected from the group consisting of Fe, Co and alloys made of Fe or Co mixed with one or more added elements selected from the group consisting of Cr, Pt, Ta, B, Mo, Pd, Cu, Au, Ti, W, Ru, Si, Ge, Nb, and Ni.  
     
     
         21 . A magnetic recording medium, comprising; 
 a first ferromagnetic layer;    a second ferromagnetic layer    a ferromagnetic coupling layer for ferromagnetically coupling said first ferromagnetic layer to said second ferromagnetic layer; and    wherein said ferromagnetic coupling layer is anti-ferromagnetically coupled to both said first ferromagnetic layer and said second ferromagnetic layer.    
     
     
         22 . The magnetic recording medium of  claim 21  wherein said ferromagnetic coupling layer further comprises two non-magnetic spacer layers separated by a magnetic interface layer.  
     
     
         23 . The magnetic recording medium of  claim 22  wherein said magnetic interface layer comprises a material selected from the group consisting of Fe, Co, FeX, and CoX, wherein said X is one or more of Cr, Pt, Ta, B, Mo, Ru, Si, Ge, Nb, and Ni.  
     
     
         24 . The magnetic recording medium of  claim 22  wherein said magnetic interface layer has a magnetic saturations greater than 300 emu/cm 3 .  
     
     
         25 . A magnetic recording medium, comprising; 
 a first ferromagnetic structure further comprising a CoCrPtB layer and Co layer;    a second ferromagnetic structure further comprising a Co layer and a CoCrPtB layer; and    a ferromagnetic coupling structure for ferromagnetically coupling said first ferromagnetic layer to said second ferromagnetic layer, said ferromagnetic coupling structure further comprising a first Ru layer, a Co layer, and a second Ru layer.    
     
     
         26 . A disc drive, comprising: 
 a magnetic recording media including a protective overcoat layer;    a motor for spinning said magnetic media about its center;    a transducer for reading and writing on said magnetic media while said magnetic media is rotated about by said motor; and    wherein said magnetic recording media further comprising: 
 a first ferromagnetic layer;  
 a second ferromagnetic layer; and  
 a ferromagnetic coupling layer to ferromagnetically couple said first ferromagnetic layer to said second ferromagnetic layer.