Abstract: A GMR spin value structure with improved performance and a method for making the same is disclosed. A key feature is the incorporation of a thin ferromagnetic insertion layer such as a 5 Angstrom thick CoFe layer between a NiCr seed layer and an IrMn AFM layer. Lowering the Ar flow rate to 10 sccm for the NiCr sputter deposition and raising the Ar flow rate to 100 sccm for the IrMn deposition enables the seed layer to be thinned to 25 Angstroms and the AFM layer to about 40 Angstroms. As a result, HEX between the AFM and pinned layers increases by up to 200 Oe while the Tb is maintained at or above 250° C. When the seed/CoFe/AFM configuration is used in a read head sensor, a higher GMR ratio is observed in addition to smaller free layer coercivity (HCF), interlayer coupling (HE), and HK values.

Abstract: It has been found that the insertion of a copper laminate within CoFe, or a CoFe/NiFe composite, leads to higher values of CPP GMR and DRA. However, this type of structure exhibits very negative magnetostriction, in the range of high ?10?6 to ?10?5. This problem has been overcome by giving the copper laminates an oxygen exposure treatment When this is done, the free layer is found to have a very low positive magnetostriction constant. Additionally, the value of the magnetostriction constant can be adjusted by varying the thickness of the free layer and/or the position and number of the oxygen treated copper laminates.

Abstract: Fe rich CoFe can be used in AP1 to enhance CPP GMR. However, this is found to degrade the electro-migration performance of the device. This problem has been solved by using an AP1 that is a laminate of several CoFe(25%) layers, separated from one another by copper layers. Ultra-thin layers of iron-rich CoFe are then inserted at all the copper-CoFe interfaces.

Abstract: It has been found that the insertion of a copper laminate within CoFe, or a CoFe/NiFe composite, leads to higher values of CPP GMR and DRA. However, this type of structure exhibits very negative magnetostriction, in the range of high ?10?6 to ?10?5. This problem has been overcome by giving the copper laminates an oxygen exposure treatment When this is done, the free layer is found to have a very low positive magnetostriction constant. Additionally, the value of the magnetostriction constant can be adjusted by varying the thickness of the free layer and/or the position and number of the oxygen treated copper laminates.

Abstract: A hard bias structure for biasing a free layer in a MR element within a read head is comprised of a composite hard bias layer having a Co78.6Cr5.2Pt16.2/Co65Cr15Pt20 configuration. The upper Co65Cr15Pt20 layer has a larger Hc value and a thickness about 2 to 10 times greater than that of the Co78.6Cr5.2Pt16.2 layer. The hard bias structure may also include a BCC underlayer such as FeCoMo which enhances the magnetic moment of the hard bias structure. Optionally, the thickness of the Co78.6Cr5.2Pt16.2 layer is zero and the Co65Cr15Pt20 layer is formed on the BCC underlayer. The present invention also encompasses a laminated hard bias structure. The Mrt value for the hard bias structure may be optimized by adjusting the thicknesses of the BCC underlayer and CoCrPt layers. As a result, a larger process window is realized and lower asymmetry output during a read operation is achieved.

Abstract: A hard bias layer that forms an abutting junction with a free layer in a GMR element and is comprised of FePtCu or FePtCuX where X is B, C, O, Si, or N is disclosed. The FePtCu layer has a composition of about 45 atomic % Fe, 45 atomic % Pt, and 10 atomic % Cu and does not require a seed layer to achieve an ordered structure. The FePtCu layer is annealed at a temperature of about 280° C. and has an Hc value more than double that of a conventional CoCrPt hard bias layer with a similar thickness. Since the FePtCu hard bias layer adjoins a free layer, it has a higher sensor edge pinning efficiency than a configuration with a CoCrPt layer on a seed layer. The novel hard bias layer is compatible with either a top or bottom spin valve structure in a GMR sensor.

Abstract: A method for fabricating a stitched CPP synthetic spin-valve sensor with in-stack stabilization of its free layer. The method can also be applied to the formation of a stitched tunneling magnetoresistive sensor. The free layer is strongly stabilized by magnetostatic coupling through the use of a longitudinal biasing formation that includes a ferromagnetic layer, denoted LBL, within the pillar portion of the sensor and a synthetic exchange coupled tri-layer within the stitched portion of the sensor. The tri-layer consists of two ferromagnetic layers, FM1 and FM2 separated by a coupling layer and magnetized longitudinally in antiparallel directions. A criterion for the magnetic thicknesses of the layers: [t(LBL)+t(FM1)]/t(FM2)=70/90 angstroms of CoFe insures a strong exchange coupling. The magnetization of the tri-layer is done in a low field anneal that does not disturb the previous magnetization of the ferromagnetic free layer.

Abstract: A current-perpendicular-to-plane (CPP) giant magnetoresistive (GMR) sensor of the synthetic spin valve type and its method of formation are disclosed, the sensor including a novel laminated free layer having ultra-thin (less than 3 angstroms thickness) laminas of Fe50 Co50 (or any iron rich alloy of the form CoxFe1-x with x between 0.25 and 0.75) interspersed with thicker layers of Co90Fe10 and Cu spacer layers to produce a free layer with good coercivity, a coefficient of magnetostriction that can be varied between positive and negative values and a high GMR ratio, due to enhancement of the bulk scattering coefficient by the laminas. The configuration of the lamina and layers in periodic groupings allow the coefficient of magnetostriction to be finely adjusted and the coercivity and GMR ratio to be optimized. The sensor performance can be further improved by including layers of Cu and Fe50Co50 in the synthetic antiferromagnetic pinned layer.

Abstract: Increases in the AP1 and AP2 thickness cause the free layer to be off-center in a CPP magnetic read head. This problem has been overcome by inserting supplementary magnetic shields within the spin valve, located as close as possible to the stack. These supplementary shields enable the read gap width to be reduced by about 430 ? and the free layer to shift back towards the center by about 30 ?.

Abstract: Replacing ruthenium with rhodium as the AFM coupling layer in a synthetically pinned CPP GMR structure enables the AP1/AP2 thicknesses to be increased. This results in improved stability and allows the free layer and AFM layer thicknesses to be decreased, leading to an overall improvement in the device performance. Another key advantage of this structure is that the magnetic annealing requirements (to establish antiparallelism between AP1 and AP2) can be significantly relaxed.

Abstract: It has been found that the insertion of a copper laminate within CoFe, or a CoFe/NiFe composite, leads to higher values of CPP GMR and DRA. However, this type of structure exhibits very negative magnetostriction, in the range of high −10−6 to −10−5. This problem has been overcome by giving the copper laminates an oxygen exposure treatment When this is done, the free layer is found to have a very low positive magnetostriction constant. Additionally, the value of the magnetostriction constant can be adjusted by varying the thickness of the free layer and/or the position and number of the oxygen treated copper laminates.