Abstract: A problem associated with current bottom spin valve designs is that it is difficult to avoid magnetic charge accumulation at the edge of the sensor area, making a coherent spin rotation during sensing difficult to achieve. This problem has been eliminated by introducing an exchange coupling layer between the free layer and the ferromagnetic layer that is used to achieve longitudinal bias for stabilization and by extending the free layer well beyond the sensor area. After all layers have been deposited, the read gap is formed by etching down as far as this layer. Since it is not critical exactly how much of the biasing layers (antiferromagnetic as well as ferromagnetic) are removed, the etching requirements are greatly relaxed. Whatever material remains in the gap is then oxidized thereby providing a capping layer as well as a good interface for specular reflection in the sensor region.

Abstract: Although it is known that exchange bias can be utilized in abutted junctions for longitudinal stabilization, a relatively large moment is needed to pin down the sensor edges effectively. Due to the inverse dependence of the exchange bias on the magnetic layer thickness, a large exchange bias has been difficult to achieve by the prior art. This problem has been solved by introducing a structure in which the magnetic moment of the bias layer has been approximately doubled by pinning it from both above and below through exchange with antiferromagnetic layers. Additionally, since the antiferromagnetic layer is in direct abutted contact with the free layer, it acts directly to help stabilize the sensor edge, which is an advantage over the traditional magnetostatic pinning that had been used.

Abstract: A problem associated with current bottom spin valve designs is that it is difficult to avoid magnetic charge accumulation at the edge of the sensor area, making a coherent spin rotation during sensing difficult to achieve. This problem has been eliminated by introducing an exchange coupling layer between the free layer and the ferromagnetic layer that is used to achieve longitudinal bias for stabilization and by extending the free layer well beyond the sensor area. After all layers have been deposited, the read gap is formed by etching down as far as this layer. Since it is not critical exactly how much of the biasing layers (antiferromagnetic as well as ferromagnetic) are removed, the etching requirements are greatly relaxed. Whatever material remains in the gap is then oxidized thereby providing a capping layer as well as a good interface for specular reflection in the sensor region.

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: A major problem in Lead Overlay design for GMR structures is that the magnetic read track width is wider than the physical read track width. This is due to high interfacial resistance between the leads and the GMR layer which is an unavoidable side effect of prior art methods. The present invention uses electroplating preceded by a wet etch to fabricate the leads. This approach requires only a thin protection layer over the GMR layer to ensure that interface resistance is minimal. Using wet surface cleaning avoids sputtering defects and plating is compatible with this so the cleaned surface is preserved Only a single lithography step is needed to define the track since there is no re-deposition involved.

Abstract: A major problem in Lead Overlay design for GMR structures is that the magnetic read track width is wider than the physical read track width. This is due to high interfacial resistance between the leads and the GMR layer which is an unavoidable side effect of prior art methods. The present invention uses electroplating preceded by a wet etch to fabricate the leads. This approach requires only a thin protection layer over the GMR layer to ensure that interface resistance is minimal. Using wet surface cleaning avoids sputtering defects and plating is compatible with this so the cleaned surface is preserved Only a single lithography step is needed to define the track since there is no re-deposition involved.

Abstract: In a conventional spin valve the shunt resistance of the pinning layer reduces the overall efficiency of the device. This problem has been overcome by using IrMn for the pinning layer at a thickness of about 20 Angstroms or less. For the IrMn to be fully effective it must be subjected to a two-step anneal, first in the presence of a high field (about 10 kOe) for several hours and then in a low field (about 500 Oe) while it cools. The result, in addition to improved pinning, is the ability to do testing at the full film and full wafer levels.

Abstract: A pinned/pinning layer configuration of the form: AP1/coupling bilayer/AP2/AFM, suitable for use in a CIP or CPP GMR sensor, a TMR sensor or an MRAM element, is found to have improved magnetic stability, yield good values of dR/R and have high values of saturation magnetization that can be adjusted to meet the requirements of magnetic field annealing. The coupling bilayer is a layer of Ru/Rh or their alloys, which provides a wide range of coupling strengths by varying either the thickness of the Ru layer or the Rh layer.

Abstract: A method for fabricating a longitudinally hard biased, bottom spin valve GMR sensor with a lead overlay (LOL) conducting lead configuration and a narrow effective trackwidth. The advantageous properties of the sensor are obtained by providing two novel barrier layers, one of which prevents oxidation of and Au diffusion into the free layer during annealing and etching and the other of which prevents oxidation of the capping layer during annealing so as to allow good electrical contact between the lead and the sensor stack.

Abstract: Prior art gains in GMR ratio resulting from use of NiFeCr as a seed layer were offset by the resulting high values obtained for Hc and Hk. This problem has been overcome by combining a seed layer of NiCr or NiFeCr with a free layer of boron doped CoFe. Additionally, when using a synthetic pinned layer, further improvement is achieved by using boron doped CoFe for the two antiparallel layers.

Abstract: A method for fabricating a longitudinally hard biased, bottom spin valve GMR sensor with a lead overlay (LOL) conducting lead configuration and a narrow effective trackwidth. The advantageous properties of the sensor are obtained by providing two novel barrier layers, one of which prevents oxidation of and Au diffusion into the free layer during annealing and etching and the other of which prevents oxidation of the capping layer during annealing so as to allow good electrical contact between the lead and the sensor stack.

Abstract: A novel seed layer comprising an approximately 30 angstrom thick layer of NiCr whose atomic percent of Cr is 31%, is used to form a single bottom spin valve read sensor and a symmetric dual spin valve read sensor having synthetic antiferromagnetic pinned layers. The seed layer permits the use of extremely thin (approximately 80 angstroms) MnPt pinning layers as well as extremely thin pinned and free layers so that the sensors can be used to read recorded media with densities exceeding 60 Gb/in2. Moreover, the high pinning field and optimum magnetostriction produces an extremely robust sensor.

Abstract: Although it is known that exchange bias can be utilized in abutted junctions for longitudinal stabilization, a relatively large moment is needed to pin down the sensor edges effectively. Due to the inverse dependence of the exchange bias on the magnetic layer thickness, a large exchange bias has been difficult to achieve by the prior art. This problem has been solved by introducing a structure in which the magnetic moment of the bias layer has been approximately doubled by pinning it from both above and below through exchange with antiferromagnetic layers. Additionally, since the antiferromagnetic layer is in direct abutted contact with the free layer, it acts directly to help stabilize the sensor edge, which is an advantage over the traditional magnetostatic pinning that had been used.

Abstract: Prior art gains in GMR ratio resulting from use of NiFeCr as a seed layer were offset by the resulting high values obtained for Hc and Hk. This problem has been overcome by combining a seed layer of NiCr or NiFeCr with a free layer of boron doped CoFe. Additionally, when using a synthetic pinned layer, further improvement is achieved by using boron doped CoFe for the two antiparallel layers.

Abstract: A method for fabricating a longitudinally hard biased, bottom spin valve GMR sensor with a lead overlay (LOL) conducting lead configuration and a narrow effective trackwidth. The advantageous properties of the sensor are obtained by providing two novel barrier layers, one of which prevents oxidation of and Au diffusion into the free layer during annealing and etching and the other of which prevents oxidation of the capping layer during annealing so as to allow good electrical contact between the lead and the sensor stack.

Abstract: A major problem in Lead Overlay design for GMR structures is that the magnetic read track width is wider than the physical read track width. This is due to high interfacial resistance between the leads and the GMR layer which is an unavoidable side effect of prior art methods. The present invention uses electroplating preceded by a wet etch to fabricate the leads. This approach requires only a thin protection layer over the GMR layer to ensure that interface resistance is minimal. Using wet surface cleaning avoids sputtering defects and plating is compatible with this so the cleaned surface is preserved Only a single lithography step is needed to define the track since there is no re-deposition involved.

Abstract: A problem associated with current bottom spin valve designs is that it is difficult to avoid magnetic charge accumulation at the edge of the sensor area, making a coherent spin rotation during sensing difficult to achieve. This problem has been eliminated by introducing an exchange coupling layer between the free layer and the ferromagnetic layer that is used to achieve longitudinal bias for stabilization and by extending the free layer well beyond the sensor area. After all layers have been deposited, the read gap is formed by etching down as far as this layer. Since it is not critical exactly how much of the biasing layers (antiferromagnetic as well as ferromagnetic) are removed, the etching requirements are greatly relaxed. Whatever material remains in the gap is then oxidized thereby providing a capping layer as well as a good interface for specular reflection in the sensor region.

Abstract: In magnetic recording applications, the continuing reduction of transducer dimensions has created a need for soft magnetic thin films with magnetic moments greater than about 22 kG are required. The present invention achieves this by use of a laminated structure made up of a thin layer of a high magnetic moment material on a layer of soft magnetic or non-magnetic material, both layers having very similar crystal structures and chemical composition, the main difference being in their nitrogen content. Such a laminate has been found to have the required high magnetic moment as well as low coercivity. The laminate is used to improve the characteristics and performance of a write head by being inserted at one or both sides of the write gap. Alternatively, the magnetic poles of the head may be constructed entirely from multiple instances of the laminate. A process for forming the laminate and applying it to the write head is also described.

Abstract: A spin valve structure that is thinner than currently available spin valves is described. This improvement is achieved through use of a thinner free layer. The key feature of the invention is the insertion of a seed enhancement layer between the seed and the free layer. The seed enhancement layer must have a FCC crystal structure, our preferred material for it being NiCu. When this layer is present, a constant GMR ratio of about 7% is obtained for a thickness range of the free layer of from 10 to 40 Angstroms. A process for manufacturing this structure is also disclosed.

Abstract: A dual stripe magnetoresistive (DSMR) sensor element, and a method for fabricating the dual stripe magnetoresistive (DSMR) sensor element. When fabricating the dual stripe magnetoresistive (DSMR) sensor element while employing the method, there are employed two pair of patterned magnetic biasing layers formed of a single magnetic biasing material. The two pair of patterned magnetic biasing layers bias a pair of patterned magnetoresistive (MR) layers in a pair of opposite canted directions.