Abstract: A tunnel junction magnetoresistive sensor having improved TMR performance (dR/R) and improved area resistance. The sensor includes a barrier layer sandwiched between a magnetic pinned layer structure and a magnetic free layer structure. The barrier layer includes a thin layer of Mg and a layer of MgOx. The barrier layer could also include a second thin layer of Mg such that the MgOx layer is sandwiched between the first and second Mg layers.

Abstract: A magnetoresistive sensor having magnetically anisotropic bias layers for biasing the free layer of the sensor. Hard bias structures for biasing the magnetization of the free layer are formed at either side of the sensor stack, and each of the hard bias structure includes a hard magnetic layer that has a magnetic anisotropy to enhance the stability of the biasing. The hard bias structure can include a Cr under-layer having a surface that has been treated by a low power angled ion milling to form it with an anisotropic surface texture. A layer of Cr—Mo alloy is formed over the Cr under-layer and the hard magnetic material layer is formed over the Cr—Mo alloy layer. The anisotropic surface texture of the Cr layer induces an aligned crystalline structure in the hard magnetic layer that causes the hard magnetic layer to have a magnetic anisotropy.

Abstract: Methods and apparatus provide improved properties of a hard bias layer of a magnetoresistance sensor. The properties of the hard bias layer are improved by using a multilayer seed structure that includes a chromium-containing layer disposed between two tungsten-containing layers.

Abstract: A current perpendicular to plane (CPP) magnetoresistive sensor having a current path defined by first and second overlying insulation layers between which an electrically conductive lead makes content with a surface of the sensor stack. The current path being narrower than the width of the sensor stack allows the outer edges of the sensor stack to be moved outside of the active area of the sensor. This results in a sensor that is unaffected by damage at outer edges of the sensor layers. The sensor stack includes a free layer that is biased by direct exchange coupling with a layer of antiferromagnetic material (AFM layer). The strength of the exchange field can be controlled by adding Cr to the AFM material to ensure that the exchange field is sufficiently weak to avoid pinning the free layer.

Abstract: A magnetoresistive sensor having a pinned layer that extends beyond the stripe height defined by the free layer of the sensor. The extended pinned layer has a strong shape induced anisotropy that maintains pinning of the pinned layer moment. The extended portion of the pinned layer has sides beyond the stripe height that are perfectly aligned with the sides of the sensor within the stripe height. This perfect alignment is made possible by a manufacturing method that uses a mask structure for more than one manufacturing phase, eliminating the need for multiple mask alignments.

Abstract: A method of manufacturing a GMR, TMR or CPP GMR sensor having a smooth interface between magnetic and non-magnetic layers to improve sensor performance by exposing a layer to a low energy ion beam prior to depositing a subsequent layer.

Abstract: A magnetoresistive sensor having magnetically anisotropic bias layers for biasing the free layer of the sensor. The hard magnetic layer is formed over a seed layer structure that has been treated to induce the magnetic anisotropy in the hard bias layers. The treated seed layers also allow the hard bias layers to be deposited over a crystalline material such as in a partial mill design, without the need for a buffer layer such as Si to break the epitaxial growth initiated by the underlying crystalline layer.

Abstract: A magnetoresistive sensor having a lead overlay defined trackwidth and a pinned layer that extends beyond the stripe height defined by the free layer of the sensor. The extended pinned layer has a strong shape induced anisotropy that maintains pinning of the pinned layer moment. The extended portion of the pinned layer has sides beyond the stripe height that are perfectly aligned with the sides of the sensor within the stripe height. This perfect alignment is made possible by a manufacturing method that uses a mask structure for more than one manufacturing phase, eliminating the need for multiple mask alignments. The lead overlay design allows narrow, accurate trackwidth definition.

Abstract: A current perpendicular to plane (CPP) magnetoresistive sensor that avoids spin torque noise while having high dr/R performance and small gap. The sensor is a dual magnetoresistive sensor having first and second pinned layers and a free layer disposed between the two pinned layers. One of the pinned layers is pinned by exchange coupling with an AFM layer, while the other pinned layer is self pinned by a shape enhanced magnetic anisotropy without the use of an AFM layer. The self pinned layer extends from the ABS to an extended stripe height distance that is greater than the stripe height distance of the AFM pinned layer and the free layer.

Abstract: A lead overlay design of a magnetic sensor is described with sensor and free layer dimensions such that the free layer is stabilized by the large demagnetization field due to the shape anisotropy. In one embodiment the giant magnetoresistive (GMR) effect under the leads is destroyed by removing the antiferromagnetic (AFM) and pinned layers above the free layer. The overlaid lead pads are deposited on the exposed spacer layer at the sides of the mask that defines the active region. In other embodiment a layer of electrically insulating material is deposited over the sensor to encapsulate it and thereby insulate it from contact with the hardbias structures. Various embodiments with self-aligned leads are also described. In a variation of the encapsulation embodiment, the insulating material is also deposited under the lead pads so the electrical current is channeled through the active region of the sensor and sidewall deposited lead pads.

Abstract: An electrically conductive etch stop layer is formed over a first electrically conductive layer. An electrically conductive diffusion barrier layer is then formed over the etch stop layer, followed by the formation of an insulator layer over the diffusion barrier layer. Utilizing an etching process with a patterned photoresist in place, insulator materials in a central region are removed to form a via which exposes electrically conductive materials in the central region. Finally, a second electrically conductive layer is formed within the via over the electrically conductive materials in the central region.

Abstract: A magnetoresistive sensor having a novel seed layer that allows a bias layer formed there over to have exceptional hard magnetic properties when deposited over a crystalline structure such as an AFM layer in a partial mill sensor design. The seed layer structure includes alternating layers of Ru and Si and a layer of CrMo formed thereover. The seed layer interrupts the epitaxial growth of an underlying crystalline structure, allowing a hard magnetic material formed over the seed layer to have a desired grain structure that is different from that of the underlying crystalline layer. The seed layer is also resistant to corrosion, providing improved sense current conduction to the sensor.

Abstract: A magnetoresistive sensor having a pinned layer that extends beyond the free layer in the stripe height direction for improved shape enhanced pinning. The sensor includes hard bias layers and leads that extend in the stripe height direction beyond the stripe height of the free layer, providing increased conductive material for improved conduction of sense current to the sensor. The hard bias layers contact the sensor stack in the region between the ABS and the stripe height of the free layer, but are electrically insulated from the pinned layer in regions beyond the stripe height of the free layer by a layer of conformally deposited non-magnetic, electrically insulating material such as alumina.

Abstract: A method is disclosed for fabricating a read head for a magnetic disk drive having a read head sensor and a hard bias layer, where the read head has a shaped junction between the read head sensor and the hard bias layer. The method includes providing a layered wafer stack to be shaped. A single- or multi-layered photoresist mask having no undercut is deposited upon the layered wafer stack to be shaped. The layered wafer stack is shaped by the output of a milling source, where the shaping includes partial milling to within a partial milling range to form a shaped junction. A hard bias layer is then deposited which is in contact with the shaped junction of the wafer stack.

Abstract: A magnetoresistive sensor having a shape enhanced pinning and a flux guide structure. First and second hard bias layers and lead layers extend from the sides of a sensor stack. The hard bias layers and leads have a stripe height that is smaller than the stripe height of a free layer, resulting in a free layer that extends beyond the back edge of the lead and hard bias layer. This portion of the free layer that extends beyond the back edge of the leads and hard bias layers provides a back flux guide. Similarly, the sensor may have a free layer that extends beyond the front edge of the lead and hard bias layers to provide a front flux guide. The pinned layer extends significantly beyond the back edge of the free layer, providing the pinned layer with a strong shape enhanced magnetic anisotropy.

Abstract: A magnetoresistive sensor having a magnetically anisotropic pinned layer structure. The pinned layer structure is formed over a seed layer having a surface that has been treated to texture the surface of the seed layer with an anisotropic roughness. This anisotropic roughness induces the magnetic anisotropy in the pinned layers. The treated seed layers also allow the pinned layer to maintain robust pinning without the need for a thick AFM layer, thereby reducing gap size.

Abstract: A magnetoresistive sensor having an improved hard bias stabilization structure. The sensor includes a hard bias layer that is formed on a surface that has been treated to form it with an anisotropic texture that induces a magnetic anisotropy oriented parallel with the air bearing surface. This magnetic anisotropy is further aided by a shape induced magnetic anisotropy caused by configuring the hard bias layers to have a width parallel with the air bearing surface that is larger than a stripe height of the hard bias layer measured perpendicular to the air bearing surface.

Abstract: A magnetoresistive sensor having improved pinning field strength. The sensor includes a pinned layer structure pinned by exchange coupling with an antiferromagnetic (AFM) layer. The AFM layer is constructed upon an under layer having treated surface with an anisotropic roughness. The anisotropic roughness, produced by an angled ion etch, results in improved pinning strength. The underlayer may include a seed layer and a thin layer of crystalline material such as PtMn formed over the seed layer. The magnetic layer may include a first sub-layer of NiFeCr and a second sub-layer of NiFe formed there over. The present invention also includes a magnetoresistive sensor having a magnetic layer deposited on an underlayer (such as a non-magnetic spacer) having a surface treated with an anisotropic texture. An AFM layer is then deposited over the magnetic layer.

Abstract: A magnetoresistive sensor having an in stack bias structure and a pinned layer having shape enhanced anisotropy. The sensor may be a partial mill design wherein the track width of the sensor is defined by the width of the free layer and the pinned layers extend beyond the trackwidth of the sensor. The sensor has an active area defined by the stripe height of the free layer. The pinned layer extends beyond the stripe height defined by the free layer, thus providing the pinned layer with the shape enhanced anisotropy. The pinned layer structure can be pinned by exchange coupling with a layer of antiferromagnetic material (AFM) layer, with pinning robustness being improved by the shape enhanced anisotropy, or can be a self pinned structure which is pinned by a combination of magnetostriction, AP coupling and shape enhanced anisostropy.

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.