Abstract: Current-perpendicular-to-plane (CPP) read sensors having constrained current paths made of lithographically-defined conductive vias with surrounding oxidized metal sublayers, and methods of making the same, are disclosed. In one illustrative example, at least part of a sensor stack structure which includes an electrically conductive spacer layer is formed. A metal (e.g. Ta) sublayer is then deposited over and adjacent the spacer layer, followed by one of an oxidation process, a nitridation process, and an oxynitridation process, to produce an insulator (e.g. TaOx) from the metal sublayer. The metal sublayer deposition and oxidation/nitridation/oxynitridation processes are repeated as necessary to form the insulator with a suitable thickness. Next, a resist structure which exposes one or more portions of the insulator is formed over the insulator. With the resist structure in place, exposed insulator materials are removed by etching to form one or more apertures through the insulator down to the spacer layer.

Abstract: A magnetic head structure for use in perpendicular magnetic recording. The magnetic head includes a magnetic write head having a return pole with a magnetic shunt structure extending from the back end opposite the ABS. The magnetic shunt structure prevents magnetic field from the write coil from reaching and affecting the read head. More specifically the shunt structure prevents magnetic field from the portion of the write coil beyond the back gap (as measured from the ABS) from magnetizing a magnetic shield of the read head. The shunt structure is also configured so as to avoid stray field writing. The size and shape of the shunt structure is therefore, limited to avoid attracting stray fields that might cause such stray field writing.

Abstract: A magnetic head having an electrostatic shunt structure for preventing damage to the magnetic head during manufacture. A portion of the shunt structure is removed during manufacture, however another portion remains. In order to prevent the remaining portions of the shunt structure from picking up stray magnetic and electromagnetic fields, an electromagnetic shield, is provided between the remaining portions of the shunt structure and the substrate.

Abstract: A method and apparatus for using a specular scattering layer in a free layer of a magnetic sensor while stabilizing the free layer by direct coupling with an antiferromagnetic layer is disclosed. A specular scattering layer is formed in a free layer of a magnetic sensor while stabilizing the free layer by direct coupling with an antiferromagnetic layer. An antiferromagnetic layer is formed abutting the free layer to provide direct exchange coupling with the free layer. The specular layer in the free layer removes any ?R degradation caused by placement of an antiferromagnetic layer over the free layer.

Abstract: A magnetoresistive sensor having employing a Mn containing Huesler alloy for improved magnetoresistive performance in a structure that minimizes corrosion and Mn migration. The sensor can be constructed with a pinned layer structure that includes a lamination of layers of Co2MnX and CoFe, where X is Al, Ge or Si. The Co2MnX can be sandwiched between the layers of CoFe to prevent Mn migration into the spacer/barrier layer. The free layer can also be constructed as a lamination of Co2MnX and CoFe layers, and may also be constructed so that the Co2MnX layer is sandwiched between CoFe layers to prevent Mn migration.

Abstract: A current perpendicular to plane (CPP) magnetoresistive sensor having a front edge that is recessed from the air bearing surface (ABS). The sensor includes a pinned layer structure a free layer structure and a spacer layer sandwiched between the free layer and the pinned layer. The free layer is an AP coupled structure that includes a first magnetic layer F1 a second magnetic layer F2 and a coupling layer sandwiched between F1 and F2. The first magnetic layer F1 extends to the ABS while the other sensor layers terminate at the recessed front edge. In this way, the F1 layer acts as a flux guide that reacts to a magnetic field from a magnetic medium. The AP coupled structure of the free layer allows each magnetic layer F1 and F2 to be thicker than would be possible in a conventional single layer free layer, which increases the GMR effect of the sensor and increases the effectiveness of the flux guide (F2).

Abstract: A magnetoresistive sensor having a free layer biased by an in stack bias layer that comprises a layer of antiferromagnetic material. The bias layer can be IrMnCr, IrMn or some other antiferromagnetic material. The free layer is a synthetic free layer having first and second magnetic layers antiparallel coupled across an AP coupling layer. The first magnetic layer is disposed adjacent to a spacer or barrier layer and the second magnetic layer is exchange coupled with the IrMnCr bias layer. The bias layer biases the magnetic moments of the free layer in desired directions parallel with the ABS without pinning the magnetic moments of the free layer.

Abstract: A magnetic write head for perpendicular magnetic recording having a trailing, wrap around magnetic shield constructed of a low magnetic permeability. The lower permeability of the shield prevents magnetic saturation of the shield, which in turn prevents adjacent track interference such as adjacent track erasure. The shield can also be constructed as a pure trailing shield, or as first and second side shields without any trailing shield portion.

Abstract: Apparatus and method for providing a magnetic head that includes a magnetoresistive read sensor disposed between first and second magnetic shields. The shields are configured to reduce protrusion of the shields from a polished flat air bearing surface of the magnetic head upon increases in temperature. This configuration for the shields therefore at least reduces differences in thermal expansion of the shields relative to other parts of the magnetic head forming the air bearing surface. These shields according to some embodiments include one or more ferromagnetic layers exchange coupled with an antiferromagnetic layer. Further, in a particular embodiment, all the ferromagnetic layers within each of the shields can have a combined thickness per shield of less than 500 angstroms.

Abstract: A method for manufacturing a magnetoresistive sensor that provides increased magnetoresistive performance. The method includes forming a series of sensor layers with at least one layer containing CoFeB, and having a first capping layer thereover. A high temperature annealing is performed to optimize the grains structure of the sensor layers. The first capping layer is then removed, such as by reactive ion etching (RIE). An antiferromagnetic layer is then deposited followed by a second capping layer. A second annealing is performed to set the magnetization of the pinned layer, the second annealing being performed at a lower temperature than the first annealing.

Abstract: A method and apparatus for providing a magnetic read sensor having a thin pinning layer and improved magnetoresistive coefficient ?R/R is disclosed. A thin IrMn alloy pinning layer is disposed adjacent a composite pinned layer, wherein the percentage of iron in the pinned layer adjacent the thin IrMn alloy pinning layer in the range of 20-40% to provide maximum pinning and the thicknesses of the outer ferromagnetic layers should be comparable.

Abstract: An improved method for the manufacture of magnetoresistive multilayer sensors is disclosed. The method is particularly advantageous for the production of magnetic tunnel junction (MTJ) sensors, which can be damaged at the air bearing surface by conventional lapping and ion milling. The disclosed process protects the ABS of the magnetoresistive sensor by depositing a diamond like carbon layer which remains in place through ion milling. The DLC layer is removed by oxidation subsequent to the formation of the ABS.

Abstract: A method for testing magnetic heads formed on a wafer to detect the presence of thermal induced popcorn noise resulting from thermal fly height control. The method includes performing a quasi test on a magnetic head, the quasi test being performed over 400 or more cycles of magnetic field application. For additional test accuracy, the write head can be cycled while 400 or more cycles of magnetic field are generated.

Abstract: A magnetoresistive tunnel junction sensor having improved free layer stability, as well as improved free sensitivity. The free layer is constructed to have a low magnetic coercivity which improves free layer sensitivity. The free layer is also constructed to have a negative magnetostriction which improves free layer stability by preventing the free layer from having an easy axis that is oriented perpendicular to die air bearing surface.

Abstract: In a magnetic tunnel junction (MTJ) device having a pinned layer and upper and lower free sublayers, to avoid loss in tunnel magnetoresistance, etching or milling of the free sublayer materials is stopped in the lower free sublayer. The upper free sublayer may be softer and thicker than the lower free sublayer to promote this, and may be doped to reduce its magnetization while maintaining physical thickness. The lower free sublayer can be made of CoFe and the upper free sublayer can made of NiFe and a dopant such as Mo or Rh.

Abstract: A method for manufacturing a magnetoresistive sensor having improved free layer biasing and track width control. The method includes forming a ferromagnetic pinned layer, and depositing a ferromagnetic film thereover. A layer of Ta is deposited over the ferromagnetic film and a mask is formed over an active sensor area. A reactive ion etch process is performed to remove selected portions of said Ta layer. An etch is then performed to remove selected portions of the ferromagnetic film in unmasked areas and a ferromagnetic refill material is deposited.

Abstract: A magnetoresistive sensor having a greatly reduced read gap. The sensor has a pinned layer structure formed above the free layer. A layer of antiferromagnetic material (AFM layer) is formed over the pinned layer structure and has a front edge disposed toward, but recessed from the air bearing surface. An electrically conductive, magnetic lead is formed over the pinned layer and AFM layer such that the lead fills a space between the AFM layer and the air bearing surface. In this way, the read gap is distance between the outermost portion of the pinned layer structure and free layer. The thickness of the AFM layer and capping layer are not included in the read gap.

Abstract: A current perpendicular to plane (CPP) giant magnetoresistive (GMR) sensor having two dual spin valves sharing a common self pinned pinned layer.

Abstract: A magnetoresisive sensor having a thin seed layer that provides an exceptionally smooth interface between layers of the sensor stack. The exceptionally smooth interface provided by the seed layer reduces interlayer exchange coupling allowing the non-magnetic spacer layer (or barrier layer) to be very thin. The seed layer includes a thin layer of Ru and a thin layer of Si which intermix to form a homogeneous, amorphous thin seed layer of Ru-silicide.

Abstract: A magnetic structure for use in a magnetic recording head, the structure having improved resistance to stray field writing. The magnetic structure can be for example a magnetic shield or a return pole of a perpendicular write element. The structure includes a main body portion which may have a generally rectangular configuration, and first and second wing portions extending laterally from the sides of the body at or near the ABS. The wing portions have a depth measured perpendicular to the ABS that is significantly less than the depth of the body portion (preferably less than 25 percent of the body portion). The wing portions may also have notches formed in their ABS edges. The wings conduct flux from the ABS edge of the body portion and create a flux choking effect for magnetic flux flowing into the wings.