Abstract: It is known that the magnetic shields, between which CPP GMR stacks are sandwiched, can be a source of AMR (anisotropic magneto-resistance) noise. This has been significantly reduced by coating both the magnetic shields with highly conductive layers. If the guidelines disclosed in the invention are followed, the read head can exhibit AMR noise reduced by about 14 to 20. Additionally, the total thickness of the read gap can be maintained to be as low as 300 to 400 Angstroms.

Abstract: Patterned, longitudinally and transversely antiferromagnetically exchange biased GMR sensors are provided which have narrow effective trackwidths and reduced side reading. The exchange biasing significantly reduces signals produced by the portion of the ferromagnetic free layer that is underneath the conducting leads while still providing a strong pinning field to maintain sensor stability. In the case of the transversely biased sensor, the magnetization of the free and biasing layers in the same direction as the pinned layer simplifies the fabrication process and permits the formation of thinner leads by eliminating the necessity for current shunting.

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: A method for forming top and bottom spin valve sensors and the sensors so formed, the sensors having a strongly coupled SyAP pinned layer and an ultra-thin antiferromagnetic pinning layer. The two strongly coupled ferromagnetic layers comprising the SyAP pinned layer in the top valve configuration are separated by a Ru spacer layer approximately 3 angstroms thick, while the two layers in the bottom spin valve configuration are separated by a Rh spacer layer approximately 5 angstroms thick. This allows the use of an ultra thin MnPt antiferromagnetic pinning layer of thickness between approximately 80 and approximately 150 angstroms. The sensor structure produced thereby is suitable for high density applications.

Abstract: As the dimensions of spin valve heads continue to be reduced, a number of difficulties are being encountered. One such is with the longitudinal bias when an external magnetic field can cause reversal of the hard magnet, thereby causing a hysteric response by the head. This coercivity reduction becomes more severe as the hard magnet becomes thinner. This problem has been overcome by inserting a decoupling layer between the antiferromagnetic layer that is used to stabilize the pinned layer of the spin valve itself and the soft ferromagnetic layer that is used for longitudinal biasing. This soft ferromagnetic layer is pinned by a second antiferromagnetic layer deposited on it on its far side away from the first antiferromagnetic layer. The presence of the decoupling layer ensures that the magnetization of the soft layer is determined only by the second antiferromagnetic layer. The inclusion of said decoupling layer allows more latitude in etch depth control during manufacturing.

Abstract: The CPP (current perpendicular to plane) design for spin valves is receiving increasing attention as track densities grow. Some of the problems associated with current designs include current induced circular domain effects, poor bias point control, and reduced sensitivity. These problems have been overcome through use of synthetic pattern exchange pinning. The invented device achieves high sensitivity by providing an extended free layer while maintaining good bias point control and edge domain control through use of exchange coupling with the whole free layer. In a second embodiment of the invention, a second spin valve is added so that the free layer receives filtered electrons from two directions. Processes to manufacture both embodiments are also described.

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: As the dimensions of spin valve heads continue to be reduced, a number of difficulties are being encountered. One such is with the longitudinal bias when an external magnetic field can cause reversal of the hard magnet, thereby causing a hysteric response by the head. This coercivity reduction becomes more severe as the hard magnet becomes thinner. This problem has been overcome by inserting a decoupling layer between the antiferromagnetic layer that is used to stabilize the pinned layer of the spin valve itself and the soft ferromagnetic layer that is used for longitudinal biasing. This soft ferromagnetic layer is pinned by a second antiferromagnetic layer deposited on it on its far side away from the first antiferromagnetic layer. The presence of the decoupling layer ensures that the magnetization of the soft layer is determined only by the second antiferromagnetic layer. The inclusion of said decoupling layer allows more latitude in etch depth control during manufacturing.

Abstract: A Spin Valve GMR and Spin Filter SVGMR configuration where in the first embodiment an important buffer layer is composed of an metal oxide having a crystal lattice constant that is close the 1st FM free layer's crystal lattice constant and has the same crystal structure (e.g., FCC, BCC, etc.). The metal oxide buffer layer enhances the specular scattering. The spin valve giant magnetoresistance (SVGMR) sensor comprises: a seed layer over the substrate. An important metal oxide buffer layer (buffer layer) over the seed layer. The metal oxide layer preferably is comprised of NiO or alpha-Fe2O3. A free ferromagnetic layer over the metal oxide layer. A non-magnetic conductor spacer layer over the free ferromagnetic layer. A pinned ferromagnetic layer (2nd FM pinned) over the non-magnetic conductor spacer layer and a pinning material layer over the pinned ferromagnetic layer. In the second embodiment, a high conductivity layer (HCL) is formed over the buffer layer to create a spin filter—SVGMR.

Abstract: A method for forming top and bottom spin valve sensors and the sensors so formed, the sensors having a strongly coupled SyAP pinned layer and an ultra-thin antiferromagnetic pinning layer. The two strongly coupled ferromagnetic layers comprising the SyAP pinned layer in the top valve configuration are separated by a Ru spacer layer approximately 3 angstroms thick, while the two layers in the bottom spin valve configuration are separated by a Rh spacer layer approximately 5 angstroms thick. This allows the use of an ultra thin MnPt antiferromagnetic pinning layer of thickness between approximately 80 and approximately 150 angstroms. The sensor structure produced thereby is suitable for high density applications.

Abstract: A Spin Valve GMR and Spin Filter SVGMR configuration where in the first embodiment an important buffer layer is composed of an metal oxide having a crystal lattice constant that is close the 1st FM free layer's crystal lattice constant and has the same crystal structure (e.g., FCC, BCC, etc.). The metal oxide buffer layer enhances the specular scattering. The spin valve giant magnetoresistance (SVGMR) sensor comprises: a seed layer over the substrate. An important metal oxide buffer layer (buffer layer) over the seed layer. The metal oxide layer preferably is comprised of NiO or alpha-Fe2O3. A free ferromagnetic layer over the metal oxide layer. A non-magnetic conductor spacer layer over the free ferromagnetic layer. A pinned ferromagnetic layer (2nd FM pinned) over the non-magnetic conductor spacer layer and a pinning material layer over the pinned ferromagnetic layer. In the second embodiment, a high conductivity layer (HCL) is formed over the buffer layer to create a spin filter -SVGMR.

Abstract: It is important for a CPP GMR read head that it have both high resistance as well as high cross-sectional area. This has been achieved by inserting a NOL (nano-oxide layer) though the middle of one or both of the two non-magnetic conductive layers. A key feature is that the NOL is formed by first depositing the conductive layer to about half its normal thickness. Then a metallic film is deposited thereon to a thickness that is low enough for it to still consist of individual islands. The latter are then fully oxidized without significantly oxidizing the conductive layer on which they lie. The remainder of the conductive layer is then deposited to a thickness sufficient to fully enclose the islands of oxide.

Abstract: In current synthetically pinned CPP SV designs, AP2 always makes a negative contribution to the device's GMR since its magnetization direction must be anti-parallel to the pinned layer (AP1). This effect has been reduced by replacing the conventional single layer AP2, that forms part of the synthetic pinned layer, with a multilayer structure into which has been inserted at least one layer of a material such as tantalum that serves to depolarize the spin of electrons that traverse its interfaces. The result is a reduction of said negative contribution by AP2, leading to a significant increase in the GMR ratio.

Abstract: As the dimensions of spin valve heads continue to be reduced, a number of difficulties are being encountered. One such is with the longitudinal bias when an external magnetic field can cause reversal of the hard magnet, thereby causing a hysteric response by the head. This coercivity reduction becomes more severe as the hard magnet becomes thinner. This problem has been overcome by inserting a decoupling layer between the antiferromagnetic layer that is used to stabilize the pinned layer of the spin valve itself and the soft ferromagnetic layer that is used for longitudinal biasing. This soft ferromagnetic layer is pinned by a second antiferromagnetic layer deposited on it on its far side away from the first antiferromagnetic layer. The presence of the decoupling layer ensures that the magnetization of the soft layer is determined only by the second antiferromagnetic layer. The inclusion of the decoupling layer allows more latitude in etch depth control during manufacturing.

Abstract: An angle adjusting device for a chair includes a fixed plate, a pivotal plate being pivotable relative to the fixed plate, a cylinder secured in the fixed plate and having an actuating pin extending out and being movable relative to the cylinder, a control rod pivotal relative to the fixed plate, and a control plate driven by the control rod and having an extension in engagement with the actuating pin of the cylinder. Pivotal movement of the control rod drives the control plate to move to initiate movement of the actuating pin of the cylinder so that pressure inside the cylinder changes to allow the legs of the pivotal plate to move along the arcuate slot, which allows the pivotal plate to change its angle relative to the fixed plate.

Abstract: As track widths of magnetic read heads grow very small, conventional longitudinal bias stabilization has been found to no longer be suitable since the strong magnetostatic coupling at the track edges also pins the magnetization of the free layer. This problem has been overcome by extending the free layer so that it is no longer confined to the area immediately below the spacer or tunneling layer. A longitudinal bias layer immediately below the free layer is given a relatively weak magnetic exchange coupling field of about 200 Oe. Although there is strong exchange coupling between this and the free layer, the degree of pinning of the free layer is low so that the device's output signal is reduced by less than about 10%. A process for manufacturing both the CPP SV and a MTJ versions of the invention is described.

Abstract: Pinned layers that are synthetically, rather than directly, pinned are desirable for a Current Perpendicular to Plane Spin Valve structure because they are more stable. However, this comes at the cost or reduced performance. The present invention solves this problem by modifying the composition of AP2. AP2 is the antiparallel layer that contacts the antiferromagnetic layer (AP1 being in contact with the pinned layer). Said modification comprises the addition of chromium or vanadium to AP2. Examples of alloys suitable for use in AP2 include NiFeCr, NiCr, CoCr, CoFeCr, and CoFeV. Additionally, the ruthenium layer normally used to effect antiferromagnetic coupling between AP1 and AP2, is replaced by a layer of chromium. The resulting structure exhibits the stability of the synthetic pin unit and the performance of the direct pin unit.

Abstract: A controlling device for a support pivotally mounted on top of a stool includes a housing adapted to securely engage with a bottom face of the support, two pawls pivotally received in the housing, a wedge and control knob connected to the wedge and a ratchet gear received in the housing. After either one of the pawls is activated, the activated pawl is able to selectively engage with the ratchet gear so that the support is able to pivot in a predetermined direction.

Abstract: Pinned layers that are synthetically, rather than directly, pinned are desirable for a Current Perpendicular to Plane Spin Valve structure because they are more stable. However, this comes at the cost or reduced performance. The present invention solves this problem by modifying the composition of AP2. AP2 is the antiparallel layer that contacts the antiferromagnetic layer (AP1 being in contact with the pinned layer). Said modification comprises the addition of chromium or vanadium to AP2. Examples of alloys suitable for use in AP2 include NiFeCr, NiCr, CoCr, CoFeCr, and CoFeV. Additionally, the ruthenium layer normally used to effect antiferromagnetic coupling between AP1 and AP2, is replaced by a layer of chromium. The resulting structure exhibits the stability of the synthetic pin unit and the performance of the direct pin unit.

Abstract: Reduction of the free layer thickness in GMR devices is desirable in order to meet higher signal requirements, besides improving the GMR ratio itself. However, thinning of the free layer reduces the GMR ratio and leads to poor thermal stability. This problem has been overcome by making AP2 from an inverse GMR material and by changing the free layer from a single uniform layer to a ferromagnetic layer AFM (antiferromagnetically) coupled to a layer of inverse GMR material. Examples of alloys that may be used for the inverse GMR materials include FeCr, NiFeCr, NiCr, CoCr, CoFeCr, and CoFeV. Additionally, the ruthenium layer normally used to effect antiferromagnetic coupling can be replaced by a layer of chromium. A process to manufacture the structure is also described.