Abstract: Systems, methods, and devices for identifying characteristics of communication cable are described. For example, a connector of a communication cable may include a set of pins. When the connector is plugged into an active device such as a transceiver, a pattern of the set of pins may be determined. This pattern may be associated with a characteristic of the communication cable (e.g., manufacture, manufacturing date, etc.).

Abstract: A method for making a current-perpendicular-to-the-plane magnetoresistive sensor structure produces a top electrode that is “self-aligned” on the top of the sensor and with a width less than the sensor trackwidth. A pair of walls of ion-milling resistant material are fabricated to a predetermined height above the biasing layers at the sensor side edges. A layer of electrode material is then deposited onto the top of the sensor between the two walls. The walls serve as a mask during angled ion milling to remove outer portions of the electrode layer. The height of the walls and the angle of ion milling determines the width of the resulting top electrode. This leaves the reduced-width top electrode located on the sensor. Because of the directional ion milling using walls that are aligned with the sensor side edges, the reduced-width top electrode is self-aligned in the center of the sensor.

Abstract: In one embodiment, a device includes a reference layer, a free layer positioned above the reference layer, and a spacer layer positioned between the reference layer and the free layer, the spacer layer providing a gap between the reference layer and the free layer, wherein the reference layer extends beyond a rear extent of the free layer in an element height direction perpendicular to a media-facing surface of the device, and wherein a rear portion of the spacer layer that extends beyond the rear extent of the free layer has an increased resistivity in comparison with a resistivity of a rest of the spacer layer. In other embodiments, a method for forming the device is presented, along with other device structures having an extended pinned layer (EPL).

Abstract: A magnetic head according to one embodiment includes an underlayer, a first nonmagnetic spacer layer above the underlayer, a free layer above the first nonmagnetic spacer layer, a second nonmagnetic spacer layer above the free layer, and a cap layer above the second nonmagnetic spacer layer. At least one of the cap layer and the underlayer comprises a soft ferromagnetic material and a high spin orbit coupling material. Other embodiments are also described.

Abstract: A current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) has a multilayer reference layer containing a Heusler alloy. The multilayer reference layer includes a crystalline non-Heusler alloy ferromagnetic layer on an antiferromagnetic layer, a Heusler alloy layer, and an intermediate crystalline non-Heusler alloy of the form CoFeX, where X is one or more of Ge, Al, Si and Ga, located between the non-Heusler alloy layer and the Heusler alloy layer. The CoFeX alloy layer has a composition (CoyFe(100-y))zX(100-z) where y is between about 10 and 90 atomic percent, and z is between about 50 and 90 atomic percent. The CoFeX alloy layer induces very strong pinning, which greatly lessens the likelihood of magnetic instability by the spin polarized electron flow from the free layer to the reference layer.

Abstract: A current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) sensor has a spacer layer that includes electrically conductive indium-zinc-oxide (IZO), i.e., In2O3 plus ZnO where the ZnO is present between 5-30 weight percent. The spacer layer may include a protective sublayer, like a layer of Ag, below the IZO layer to prevent oxidation of the reference layer from the oxygen in the IZO layer. The spacer layer includes a top layer consisting essentially of Zn located above the IZO layer below the free layer. Measurements from a large number of CPP-GMR sensors with spacer layers of Ag(9 ?)/IZO(20 ?)/Zn(8 ?) show ?R/R values of about 15-17% and acceptable RA values of around 100 m?·?m2.

Abstract: A current-perpendicular-to-the-plane magnetoresistive sensor has an antiparallel free (APF) structure and soft side shields wherein the upper free layer (FL2) of the APF structure is magnetically coupled antiparallel to the top shield and a top shield seed layer via a nonmagnetic antiparallel coupling (APC) layer. In one embodiment the antiparallel coupling is through an antiferromagnetic-coupling (AFC) layer that provides a dominant antiferromagnetic indirect exchange coupling of FL2 to the top shield. In another embodiment the antiparallel coupling is by an APC layer that decouples FL2 and the top shield and causes the edge-induced magnetostatic coupling between FL2 and the seed layer to dominate. The degree of coupling is controlled by the composition and thickness of the nonmagnetic APC layer between FL2 and the seed layer, and by the thickness of the seed layer.

Abstract: A magnetic head according to one embodiment includes an underlayer, a first nonmagnetic spacer layer above the underlayer, a free layer above the first nonmagnetic spacer layer, a second nonmagnetic spacer layer above the free layer, and a cap layer above the second nonmagnetic spacer layer. At least one of the cap layer and the underlayer comprises a soft ferromagnetic material and a high spin orbit coupling material. Other embodiments are also described.

Abstract: A current-perpendicular-to-the-plane magnetoresistive sensor has an antiparallel free (APF) structure and soft side shields wherein the upper free layer (FL2) of the APF structure is magnetically coupled antiparallel to the top shield and a top shield seed layer via a nonmagnetic antiparallel coupling (APC) layer. In one embodiment the antiparallel coupling is through an antiferromagnetic-coupling (AFC) layer that provides a dominant antiferromagnetic indirect exchange coupling of FL2 to the top shield. In another embodiment the antiparallel coupling is by an APC layer that decouples FL2 and the top shield and causes the edge-induced magnetostatic coupling between FL2 and the seed layer to dominate. The degree of coupling is controlled by the composition and thickness of the nonmagnetic APC layer between FL2 and the seed layer, and by the thickness of the seed layer.

Abstract: A current-perpendicular-to-the plane magnetoresistive sensor has top and bottom electrodes narrower than the sensor trackwidth. The electrodes are formed of one of Cu, Au, Ag and AgSn, which have an ion milling etch rate much higher than the etch rates for the sensor's ferromagnetic materials. Ion milling is performed at a high angle relative to a line orthogonal to the plane of the electrode layers and the layers in the sensor stack. Because of the much higher etch rate of the material of the top and bottom electrode layers, the electrode layers will have side edges that are recessed from the side edges of the free layer. This reduces the surface areas for the top and bottom electrodes, which causes the sense current passing through the sensor's free layer to be confined in a narrower channel, which is equivalent to having a sensor with narrower physical trackwidth.

Abstract: The present invention generally relates to a write head pole laminate structure. The write head pole structure can include multiple multi-layer magnetic structures that are separated by a non-magnetic material that is amorphous or microcrystalline. Each multi-layer magnetic structure includes one or more first magnetic layers that are spaced from one or more second magnetic layers by a non-magnetic layer such that the one or more first magnetic layers are substantially identical to the one or more second magnetic layers. In such a design, the one or more second magnetic layers are antiparallel to the one or more first magnetic layers so that a zero total net magnetic moment is present for the multi-layer magnetic structure when current is removed from the write head pole.

Abstract: A current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) has a multilayer reference layer containing a Heusler alloy. The multilayer reference layer includes a crystalline non-Heusler alloy ferromagnetic layer on an antiferromagnetic layer, a Heusler alloy layer, and an intermediate crystalline non-Heusler alloy of the form CoFeX, where X is one or more of Ge, Al, Si and Ga, located between the non-Heusler alloy layer and the Heusler alloy layer. The CoFeX alloy layer has a composition (CoyFe(100-y))zX(100-z) where y is between about 10 and 90 atomic percent, and z is between about 50 and 90 atomic percent. The CoFeX alloy layer induces very strong pinning, which greatly lessens the likelihood of magnetic instability by the spin polarized electron flow from the free layer to the reference layer.

Abstract: A dual current-perpendicular-to-the-plane magnetoresistive (CPP-MR) sensor has an antiparallel-free (APF) structure as the free layer and uses the top and bottom shields as reference layers. The free layer is an APF structure that has the two free layers (FL1 and FL2) biased into a “spin-flop” state. In this state, the magnetic bias field from side biasing layers is great enough to stabilize the magnetizations of FL1 and FL2 to have a relative orientation preferably about 90 degrees and symmetrically positioned on either side of the magnetic bias field. The side biasing layers may be formed of soft magnetic material to also function as side shields and the top shield may be ferromagnetically coupled to the side shields, with the magnetization of the top shield being opposite that of the magnetization of the bottom shield.

Abstract: A current-perpendicular-to-the plane magnetoresistive sensor has top and bottom electrodes narrower than the sensor trackwidth. The electrodes are formed of one of Cu, Au, Ag and AgSn, which have an ion milling etch rate much higher than the etch rates for the sensor's ferromagnetic materials. Ion milling is performed at a high angle relative to a line orthogonal to the plane of the electrode layers and the layers in the sensor stack. Because of the much higher etch rate of the material of the top and bottom electrode layers, the electrode layers will have side edges that are recessed from the side edges of the free layer. This reduces the surface areas for the top and bottom electrodes, which causes the sense current passing through the sensor's free layer to be confined in a narrower channel, which is equivalent to having a sensor with narrower physical trackwidth.

Abstract: A method for making a current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor that has a reference layer with low coercivity includes first depositing, within a vacuum chamber, a seed layer and an antiferromagnetic layer on a substrate without the application of heat. The substrate with deposited layers is then heated to between 200-600° C. for between 1 to 120 minutes. The substrate with deposited layers is then cooled, preferably to room temperature (i.e., below 50° C., but to at least below 100° C., in the vacuum chamber. After cooling of the antiferromagnetic layer, the ferromagnetic reference layer is deposited on the antiferromagnetic layer. Then the substrate with deposited layers is removed from the vacuum chamber and subjected to a second annealing, in the presence of a magnetic field, by heating to a temperature between 200-400° C. for between 0.5-50 hours.

Abstract: A method for making a current-perpendicular-to-the-plane magnetoresistive sensor structure produces a top electrode that is “self-aligned” on the top of the sensor and with a width less than the sensor trackwidth. A pair of walls of ion-milling resistant material are fabricated to a predetermined height above the biasing layers at the sensor side edges. A layer of electrode material is then deposited onto the top of the sensor between the two walls. The walls serve as a mask during angled ion milling to remove outer portions of the electrode layer. The height of the walls and the angle of ion milling determines the width of the resulting top electrode. This leaves the reduced-width top electrode located on the sensor. Because of the directional ion milling using walls that are aligned with the sensor side edges, the reduced-width top electrode is self-aligned in the center of the sensor.

Abstract: A method for making a current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor that has a reference layer with low coercivity includes first depositing, within a vacuum chamber, a seed layer and an antiferromagnetic layer on a substrate without the application of heat. The substrate with deposited layers is then heated to between 200-600° C. for between 1 to 120 minutes. The substrate with deposited layers is then cooled, preferably to room temperature (i.e., below 50° C., but to at least below 100° C., in the vacuum chamber. After cooling of the antiferromagnetic layer, the ferromagnetic reference layer is deposited on the antiferromagnetic layer. Then the substrate with deposited layers is removed from the vacuum chamber and subjected to a second annealing, in the presence of a magnetic field, by heating to a temperature between 200-400° C. for between 0.5-50 hours.

Abstract: A method and apparatus for increasing the electrical resistivity and corrosion resistance of the material forming a spacer layer in current-perpendicular-to-the-plane (CPP) giant magnetoresistive (GMR) sensors. The increased resistivity of the spacer layer, and thus, the CPP-GMR sensor permits a larger voltage across the sensor and a higher signal-to-noise ratio. The increased corrosion resistance of the spacer layer minimizes the effects of exposing the spacer layer to corrosive materials during fabrication. For example, adding tin to silver to form a metallic alloy spacer layer increases the corrosion resistance of the spacer layer and the electrical resisitivity of the CPP-GMR sensor relative to a spacer layer consisting solely of silver. The Ag—Sn alloy permits a larger current to flow through the sensor, which increases the signal-to-noise ratio.

Abstract: An air-bearing slider used in a magnetic recording disk drive has a surface that supports a magnetoresistive (MR) read head or sensor and an electrical lapping guide (ELG) adjacent to the MR sensor. The ELG is formed of a different material than the MR sensor so as to have both a high electrical resistivity and a substantially higher etch rate. When the ELG and MR sensor are etched simultaneously to form their respective back edges, the ELG will have a sharp well-defined non-tapered wall at the back edge. The ELG has a film thickness close to but generally thinner than that of the MR sensor, and a sheet resistance to generally match the resistance measurement capability of the lapping tool. The preferred material for the ELG is an alloy comprising silver (Ag) and one or more of Sn, Ge and zinc Zn.

Abstract: A scissoring-type CPP-MR sensor has the two free ferromagnetic layers formed as exchange-coupled structures. Each exchange-coupled structure includes a patterned layer formed of alternating stripes of ferromagnetic stripes and nonmagnetic stripes, and a continuous unpatterned ferromagnetic layer in contact with and exchange-coupled to the ferromagnetic stripes of the patterned layer. The ferromagnetic stripes have a length-to-width aspect ratio of at least 2, which results in increased uniaxial anisotropy of the exchange-coupled unpatterned ferromagnetic layer. The stripes are oriented at an acute angle relative to the disk-facing surface of the sensor, and the stripes of the first free layer are generally orthogonal to the stripes of the second free layers. A hard magnet layer is magnetized in a direction orthogonal to the disk-facing surface for biasing the magnetization directions of the unpatterned ferromagnetic layers in the first and second free layers generally orthogonal to one another.