Abstract: A current-to-perpendicular-to-plane (CPP) read sensor with multiple reference layers and associated fabrication methods are disclosed. According to one embodiment, the multiple reference layers of a CPP read sensor include a first reference layer (e.g., Co—Fe) formed by a ferromagnetic polycrystalline film, a second reference layer (e.g., Co—Fe—Hf) formed by a ferromagnetic amorphous film, a third reference layer (e.g., Co—Fe—B) formed by a ferromagnetic amorphous film, and a fourth reference layer (e.g., Co—Fe) formed by a ferromagnetic polycrystalline film. A plasma treatment is applied to the fourth reference layer for surface smoothening, and no replenishment is needed as long as the fourth reference layer is not completely removed after the plasma treatment. The fourth reference layer protects the surface of the third reference layer from spin polarization deterioration caused by the plasma treatment, thereby maintaining a strong TMR or GMR effect.

Abstract: A read sensor stabilized by bidirectional anisotropy is disclosed. The read sensor includes a longitudinal flux-closure structure comprising an antiferromagnetic pinning layer, a ferromagnetic bias layer, a nonmagnetic spacer layer, and a ferromagnetic sense layer. In this longitudinal flux-closure structure, the antiferromagnetic pinning layer directly couples to the ferromagnetic bias layer inducing strong unidirectional anisotropy, and also indirectly couples to the ferromagnetic sense layer inducing weak unidirectional anisotropy. In addition, the ferromagnetic bias layer antiparallel-couples to the ferromagnetic sense layer across the nonmagnetic spacer layer inducing optimal bidirectional anisotropy. The magnetization of the ferromagnetic bias layer thus remains rigidly pinned mainly due to the strong unidirectional anisotropy, while the magnetization of the ferromagnetic sense layer can rotate freely and stably due to the optimal bidirectional anisotropy.

Abstract: A method and apparatus providing a stabilized top shield in a read head used for the longitudinal or perpendicular magnetic recording is disclosed. The top shield includes a laminate structure including at least three layers of ferromagnetic and antiferromagnetic films in a frame. Unidirectional anisotropy induced at the interface of the ferromagnetic and antiferromagnetic films is optimized by selecting suitable compositions and thicknesses to achieve the stabilization of the top shield while maintaining high permeability. In an alternative method, the top shield includes a ferromagnetic Ni—Fe film in a central region and multiple layers comprising ferromagnetic Co—Fe and Ni—Fe layers and an antiferromagnetic layer.

Abstract: The invention provides a current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with multiple ferromagnetic sense layers. In one embodiment of the invention, a CPP TMR read sensor comprises a first sense layer formed by a ferromagnetic polycrystalline Co—Fe film, a second sense layer formed by a ferromagnetic interstitial-type amorphous Co—Fe— B film, a third sense layer formed by a ferromagnetic substitute-type amorphous Co—Fe—X film where X is Hf, Zr or Y, and a fourth sense layer formed by a ferromagnetic Ni—Fe film. The third sense layer acts as a diffusion barrier layer to suppress Ni diffusion, thus allowing the incorporation of the Ni—Fe fourth sense layer for improving ferromagnetic properties of the multiple sense layers. The multiple sense layers induce spin-dependent scattering, thus facilitating the CPP TMR read sensor to exhibit a strong TMR effect.

Abstract: A read sensor with a uniform longitudinal bias (LB) stack is proposed. The read sensor is a giant magnetoresistance (GMR) sensor used in a current-in-plane (CIP) or a current-perpendicular-to-plane (CPP) mode, or a tunneling magnetoresistance (TMR) sensor used in the CPP mode. The transverse pinning layer of the read sensor is made of an antiferromagnetic Pt—Mn, Ir—Mn or Ir—Mn—Cr film. In one embodiment of this invention, the uniform LB stack comprises a longitudinal pinning layer, preferable made of an antiferromagnetic Ir—Mn—Cr or Ir—Mn film, in direct contact with and exchange-coupled to sense layers of the read sensor. In another embodiment of the present invention, the uniform LB stack comprises the Ir—Mn—Cr or Ir—Mn longitudinal pinning layer exchange coupled to a ferromagnetic longitudinal pinned layer, and a nonmagnetic antiparallel-coupling spacer layer sandwiched between and the ferromagnetic longitudinal pinned layer and the sense layers.

Abstract: A current-to-perpendicular-to-plane (CPP) read sensor with multiple reference layers and associated fabrication methods are disclosed. According to one embodiment of the invention, the multiple reference layers of a CPP tunneling magnetoresistance (TMR) read sensor includes a first reference layer formed by a ferromagnetic polycrystalline Co—Fe film, a second reference layer formed by a ferromagnetic substitute-type amorphous Co—Fe—X film where X is Hf, Zr or Y, and a third reference layer formed by a ferromagnetic interstitial-type amorphous Co—Fe—B film. The first reference layer facilitates the CPP TMR read sensor to exhibit high exchange and antiparallel-coupling fields. The second reference layer provides a thermally stable flat surface, thus facilitating the CPP TMR read sensor to exhibit a low ferromagnetic-coupling field. The multiple reference layers may induce spin-dependent scattering, thus facilitating the CPP TMR sensor to exhibit a high TMR coefficient.

Abstract: A giant magnetoresistance (GMR) sensor with strongly pinning and pinned layers is described for magnetic recording at ultrahigh densities. The pinning layer is an antiferromagnetic (AFM) iridium-manganese-chromium (Ir—Mn—Cr) film having a Mn content of approximately from 70 to 80 atomic percent and having a Cr content of approximately from 1 to 10 atomic percent. The first pinned layer is preferably a ferromagnetic Co—Fe having an Fe content of approximately from 20 to 80 at % and having high, positive saturation magnetostriction. The second pinned layer is preferably a ferromagnetic Co—Fe having an Fe content of approximately from 0 to 10 atomic percent. The net magnetic moment of the first and second pinned layers is designed to be nearly zero in order to achieve a pinning field of beyond 3,000 Oe.

Abstract: A method, apparatus, and article of manufacture for a current-perpendicular-to-plane (CPP) giant magnetoresistance (GMR) or a tunneling magnetoresistance (TMR) read sensor is proposed. The CPP read sensor comprises an amorphous ferromagnetic first seed layer, a polycrystalline nonmagnetic second seed layer, a nonmagnetic first cap layer, a nonmagnetic second cap layer, and a ferromagnetic third gap layer. A read gap is defined by a distance between the ferromagnetic first seed layer and the ferromagnetic third cap layer.

Abstract: A magnetoresistive sensor having a well defined track width and method of manufacture thereof.

Abstract: A method of forming a barrier layer of a tunneling magnetoresistive (TMR) device by forming first and second MgO barrier layers by different sputtering methods, but in the same sputtering system module. A first magnesium-oxide (MgO) barrier layer is formed over one of the TMR device's ferromagnetic layers by a DC magnetron sputter deposition from an Mg target in an oxygen environment. In the same module, a second MgO barrier layer is formed over the first MgO film by an RF sputter deposition from an MgO target and in an environment free of oxygen. Prior to the formation of the first MgO barrier layer, an optional Mg protection layer can be deposited on the ferromagnetic layer and oxidized by a first optional oxygen treatment. After deposition of the first MgO barrier layer, a second optional oxygen treatment may be conducted. After deposition of the second MgO barrier layer, a second Mg protection layer may be deposited by DC sputter deposition, followed by an optional third oxygen treatment.

Abstract: A method is disclosed for fabricating a read sensor for a magnetic head for a hard disk drive having a read sensor stack and two lateral stacks. The method of fabrication includes forming lateral stacks on a gap layer, surrounding a groove to form a template. The read sensor stack is then formed in the groove, which defines the lateral dimensions of the read sensor stack, and lead layers are then formed on the lateral stacks. Also disclosed is a read head for a disk drive having a sensor stack defined by pre-established lateral stacks, and a disk drive having the read head.

Abstract: One illustrative method of fabricating a read sensor of a magnetic head includes the steps of forming a plurality of read sensor layers on a wafer; etching the read sensor layers to form a read sensor structure with a trench in front of the read sensor structure; forming a highly porous material within the trench; and slicing the wafer and lapping the sliced wafer through the highly porous material until an air bearing surface (ABS) of the magnetic head is reached. Advantageously, the highly porous material in front of the read sensor structure reduces mechanical stress on the read sensor during the lapping process. This reduces the likelihood that the amplitude of the read sensor will be degraded or set in a “flipped” or reversed orientation, as well as reduces the likelihood that electrostatic discharge (ESD) damage to the read sensor will occur.

Abstract: Methods of making a read sensor with a selectively deposited lead layers are disclosed. In one illustrative example, the method includes the acts of forming a plurality of read sensor layers over a wafer; forming a monolayer photoresist to mask the plurality of read sensor layers in a central region; ion milling to remove the unmasked plurality of read sensor layers in side regions to thereby form a read sensor in the central region; depositing longitudinal bias layers in the side regions; and depositing a silicon reactant layer over the longitudinal bias layers in the side regions. After removing the monolayer photoresist, a silicon reduction process and a hydrogen reduction process are sequentially performed for the selective depositions of the lead material.

Abstract: A giant magnetoresistance (GMR) sensor with side longitudinal bias (LB) stacks is proposed for magnetic recording at ultrahigh densities. The GMR sensor extends from a read region into two side regions. The side LB stacks overlies the GMR sensor in the two side regions, rigidly pinning sense layers through antiparallel coupling across an antiparallel coupling spacer layer. Magnetostatic interactions occur in the sense layers between the read and side regions, thereby stabilizing the sense layers in the read region.

Abstract: A method for manufacturing a tunnel junction magnetoresistive sensor having improved magnetic performance and reliability. The method includes depositing a Mg—O barrier layer in a sputter deposition tool in a chamber having an oxygen concentration that changes. For example, the sputter deposition could be initiated with a first oxygen concentration in the chamber, and then, during the deposition of the barrier layer the oxygen concentration can be reduced.

Abstract: A tunneling magnetoresistive (TMR) sensor with a free layer made of a Co—Fe—B alloy is disclosed. After annealing at a temperature of less than 300° C., the Co—Fe—B free layer exhibits a negative or zero saturation magnetostriction, ?S, while the TMR sensor exhibits superior TMR properties. The Co—Fe—B free layer has an Fe content of not greater than 10 atomic percent, and a B content of not greater than 10 atomic percent. Alternatively, a free-layer structure is used in place of the Co—Fe—B free layer The free-layer structure includes a first free layer lying on a barrier layer and a second free layer lying on the first free layer. The first free layer is made of an alloy selected from Co—Fe, Co—B and Co—Fe—B alloys, while the second free layer is made of an alloy selected from Co—B and Co—Fe—B alloys. The first free layer has an Fe content of not greater than 10 atomic percent, and a B content of not greater than 10 atomic percent.

Abstract: A read sensor with a uniform longitudinal bias (LB) stack is proposed. The read sensor is a giant magnetoresistance (GMR) sensor used in a current-in-plane (CIP) or a current-perpendicular-to-plane (CPP) mode, or a tunneling magnetoresistance (TMR) sensor used in the CPP mode. The transverse pinning layer of the read sensor is made of an antiferromagnetic Pt—Mn, Ir—Mn or Ir—Mn—Cr film. In one embodiment of this invention, the uniform LB stack comprises a longitudinal pinning layer, preferable made of an antiferromagnetic Ir—Mn—Cr or Ir—Mn film, in direct contact with and exchange-coupled to sense layers of the read sensor. In another embodiment of the present invention, the uniform LB stack comprises the Ir—Mn—Cr or Ir—Mn longitudinal pinning layer exchange coupled to a ferromagnetic longitudinal pinned layer, and a nonmagnetic antiparallel-coupling spacer layer sandwiched between and the ferromagnetic longitudinal pinned layer and the sense layers.

Abstract: A dual spin valve (SV) sensor is provided with a longitudinal bias stack sandwiched between a first SV stack and a second SV stack. The longitudinal bias stack comprises an antiferromagnetic (AFM) layer sandwiched between first and second ferromagnetic layers. The first and second SV stacks comprise antiparallel (AP)-pinned layers pinned by AFM layers made of an AFM material having a higher blocking temperature than the AFM material of the bias stack allowing the AP-pinned layers to be pinned in a transverse direction and the bias stack to be pinned in a longitudinal direction. The demagnetizing fields of the two AP-pinned layers cancel each other and the bias stack provides flux closures for the sense layers of the first and second SV stacks.

Abstract: A current-perpendicular-to-plane (CPP) magnetoresistance sensor and a method for forming a current-perpendicular-to-plane (CPP) magnetoresistance sensor. The method includes providing a ferromagnetic shield layer and disposing one or more seed layers on the ferromagnetic shield layer. The method also includes disposing a pinning layer on the one or more seed layers, wherein the pinning layer excludes PtMn, and disposing a pinned layer on the pinning layer. The shield layer, each of the one or more seed layers, the pinning layer, and the pinned layer are comprised of compounds having face-centered-cubic structures.

Abstract: A read sensor with a uniform longitudinal bias (LB) stack is proposed. The read sensor is a giant magnetoresistance (GMR) sensor used in a current-in-plane (CIP) or a current-perpendicular-to-plane (CPP) mode, or a tunneling magnetoresistance (TMR) sensor used in the CPP mode. The transverse pinning layer of the read sensor is made of an antiferromagnetic Pt—Mn, Ir—Mn or Ir—Mn—Cr film. In one embodiment of this invention, the uniform LB stack comprises a longitudinal pinning layer, preferable made of an antiferromagnetic Ir—Mn—Cr or Ir—Mn film, in direct contact with and exchange-coupled to sense layers of the read sensor. In another embodiment of the present invention, the uniform LB stack comprises the Ir—Mn—Cr or Ir—Mn longitudinal pinning layer exchange coupled to a ferromagnetic longitudinal pinned layer, and a nonmagnetic antiparallel-coupling spacer layer sandwiched between and the ferromagnetic longitudinal pinned layer and the sense layers.