Abstract: An array of SMT MRAM cells has a read reference circuit that provides a reference current that is the sum of a minimum current through a reference SMT MRAM cell programmed with a maximum resistance and a maximum current through an reference SMT MRAM cell programmed with a minimum resistance. The reference current forms an average reference voltage at the reference input of a sense amplifier for reading a data state from selected SMT MRAM cells of the array such that the reference SMT MRAM cells will not be disturbed during a read operation. The read reference circuit compensates for current mismatching in the reference current caused by a second order non matching effect.

Abstract: A PMR writer in a read/write head is disclosed wherein an upper shield covering the coil layer is comprised of a magnetic layer optimized for magnetic performance and a second layer used for tuning mechanical protrusion. The composite layer simultaneously provides high saturation magnetization and high permeability from the magnetic layer and low CTE from the second layer which tunes the relative spacing between the writer, reader, and the rest of the slider. In one embodiment, first and second write shields are formed on a write gap layer and have front portions at the ABS and back portions in a back gap region. The upper write shield connects on one side with the second write shield at the ABS and on a second side with the back gap region. This design can yield better reader and writer spacing for the same physical clearance which enables products with higher recording density.

Abstract: A system and method for measuring the modulation between a magnetic head and a magnetic storage medium, such as a disk, is disclosed. A magnetic read/write head is positioned above a magnetic storage medium at a given flying height. The magnetic read/write head reads a signal from the magnetic storage medium. A tester measures an alternating electric current between the magnetic read/write head through the slider and the magnetic storage medium. A computer may then calculate the modulation by the magnetic read/write head based on the alternating electric current. A DC voltage to the head may be applied to lower the flying height of the magnetic head.

Abstract: Formation of a bottom electrode for an MTJ device on a silicon nitride substrate is facilitated by including a protective coating that is partly consumed during etching of the alpha tantalum portion of said bottom electrode. Adhesion to SiN is enhanced by using a TaN/NiCr bilayer as “glue”.

Abstract: A method of forming a CPP MTJ MRAM element that utilizes transfer of spin angular momentum as a mechanism for changing the magnetic moment direction of a free layer. The device includes a tunneling barrier layer of MgO and a non-magnetic CPP layer of Cu or Cr and utilizes a novel synthetic free layer having three ferromagnetic layers mutually exchange coupled in pairwise configurations. The free layer comprises an inner ferromagnetic and two outer ferromagnetic layers, with the inner layer being ferromagnetically exchange coupled to one outer layer and anti-ferromagnetically exchange coupled to the other outer layer. The ferromagnetic coupling is very strong across an ultra-thin layer of Ta, Hf or Zr of thickness preferably less than 0.4 nm.

Abstract: A MTJ that minimizes spin-transfer magnetization switching current (Jc) in a Spin-RAM to <1×106 A/cm2 is disclosed. The MTJ has a Co60Fe20B20/MgO/Co60Fe20B20 configuration where the CoFeB AP1 pinned and free layers are amorphous and the crystalline MgO tunnel barrier is formed by a ROX or NOX process. The capping layer preferably is a Hf/Ru composite where the lower Hf layer serves as an excellent oxygen getter material to reduce the magnetic “dead layer” at the free layer/capping layer interface and thereby increase dR/R, and lower He and Jc. The annealing temperature is lowered to about 280° C. to give a smoother CoFeB/MgO interface and a smaller offset field than with a 350° C. annealing. In a second embodiment, the AP1 layer has a CoFeB/CoFe configuration wherein the lower CoFeB layer is amorphous and the upper CoFe layer is crystalline to further improve dR/R and lower RA to ?10 ohm/?m2.

Abstract: Systems and methods to minimize signal loss and distortions with connections of audio sources and speakers are disclosed. Fiber optic cables are used instead of conventional cables. The audio signals are kept always in the analog domain, no matter if they are in optical or electric format. The strength of the audio signals can be controlled by a volume control unit. A small amplifier unit can either directly plugged to speakers are connected to the speakers via a short speaker cable. A preamplifier is no more necessary in the system.

Abstract: A perpendicular magnetic recording (PMR) head is fabricated with a multi-level tapered write pole for efficient channeling of magnetic flux. The write pole comprises a main pole with a tapered tip on which is formed at least one yoke that has a tapered edge. The edge of the yoke is recessed from the ABS of the tapered tip, giving the write pole a stepped profile. The tapered tip can be two sloped surfaces that are symmetric about a mid-plane of the main pole or a single sloped edge on the leading side or the trailing side of the pole. The yoke structure can consist of a single yoke formed on one side of the main pole or it can consist of two yokes formed symmetrically on both the leading and trailing sides of the main pole.

Abstract: Using a beam of xenon ions together with a suitable mask, a stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal having sidewalls, including a vertical section and a shortened taper portion, has been formed. This is followed by formation of conductive lead layers as needed. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.

Abstract: A composite free layer having a FL1/insertion/FL2 configuration where a top surface of FL1 is treated with a weak plasma etch is disclosed for achieving enhanced dR/R while maintaining low RA, and low ? in TMR or GMR sensors. The weak plasma etch removes less than about 0.2 Angstroms of FL1 and is believed to modify surface structure and possibly increase surface energy. FL1 may be CoFe, CoFe/CoFeB, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, or Nb having a (+) ? value. FL2 may be CoFe, NiFe, or alloys thereof having a (?) ? value. The thin insertion layer includes at least one magnetic element such as Co, Fe, and Ni, and at least one non-magnetic element selected from Ta, Ti, W, Zr, Hf, Nb, Mo, V, Cr, or B. When CoFeBTa is selected as insertion layer, the CoFeB:Ta ratio is from 1:1 to 4:1.

Abstract: A gate voltage boosting circuit provides a voltage boost to a gate of a select switching MOS transistor of a spin-torque MRAM cell to prevent a programming current reduction through an MTJ device of the spin-torque MRAM cell. A spin-torque MRAM cell array is composed of spin-torque MRAM cells that include a MTJ element and a select switching device. A local word line is associated with one row of the plurality of spin-torque MRAM cells and is connected to a gate terminal of the select switching devices of the row of MRAM cells to control activation and deactivation. One gate voltage boosting circuit is placed between an associated global word line and an associated local word line. The gate voltage boosting circuits boost a voltage of a gate of the selected switching device during writing of a logical “1” to the MTJ element of a selected spin-torque MRAM cell.

Abstract: A waveguide structure for aligning a light source to a center waveguide (CWG) in a TAMR head is disclosed and includes two alignment waveguides (AWVG) symmetrically formed about a plane that bisects the CWG lengthwise dimension. Each AWVG has a light coupling section formed parallel to a side of the CWG and captures 0.5% to 10% of the light in the CWG. Each AWVG has an outlet that directs light to a photo detector or camera so that light intensity measurements lAWVG1 and lAWVG2 for first and second AWVG, respectively, can be taken at various positions of the light source. Optimum alignment occurs when (lAWVG1+lAWVG2) reaches a maximum value and |lAWVG1?lAWVG2| has a minimum value. AWVG outlets may be at the ABS, or at the side or back end of a slider. Measurement sensitivity is increased by decreasing the width of the AWVG.

Abstract: An apparatus and a general method to measure a magnetic field using magneto-resistive sensors in an open-loop configuration are disclosed. A key feature is the regular in-situ normalization of the sensors to compensate for the effects of sensor aging.

Abstract: A magnetic shield in which all domain patterns and orientations are stable and which are consistently repeated each time the shield is exposed to an initialization field, is disclosed. This is achieved by giving it a suitable shape which ensures that all closure domains can align themselves at a reduced angle relative to the initialization direction while still being roughly antiparallel to each other. Most, though not all, of these shapes are variations on trapezoids.

Abstract: A waveguide structure for a TAMR head is disclosed wherein at least one detection waveguide is formed parallel to a main waveguide and located a gap distance therefrom. A light source transmits light into the main waveguide and towards an ABS/medium interface. A plasmon generator converts light from the waveguide into plasmon waves that are directed onto a magnetic medium. Back reflected light is captured by the main waveguide, partially diverted into a detection waveguide, and transmitted to a photo detector that measures light intensity (IB) which correlates closely to the plasmon wave intensity at the ABS/medium interface. A controller linked to the photo detector is employed to calculate IB as a function of ABS/medium spacing in a non-write condition and this relationship can be used to control and maintain a constant plasmon wave intensity at the ABS during a series of TAMR write processes with a plurality of media.

Abstract: A PMR writer with a tapered main pole layer and tapered non-magnetic top-shaping layer is disclosed that minimizes trailing shield saturation. A second non-magnetic top shaping layer may be employed to reduce the effective TH size while the bulk of the trailing shield is thicker to allow a larger process window for back end processing. A sloped surface with one end at the ABS and a second end 0.05 to 0.3 microns from the ABS is formed at a 10 to 80 degree angle to the ABS and includes a sloped surface on the upper portion of the main pole layer and on the non-magnetic top shaping layer. An end is formed on the second non-magnetic top shaping layer at the second end of the sloped surface followed by forming a conformal write gap layer and then depositing the trailing shield on the write gap layer and along the ABS.

Abstract: A PMR writer is disclosed wherein one or more of a trailing shield, leading shield, and side shields are composites with a first section made of an anisotropic (-Ku) magnetic layer adjoining a gap layer and a second section comprised of an isotropic soft magnetic layer formed on a side of the first section that faces away from the main pole. There may be a non-magnetic Ru layer between each first and second section to prevent interlayer coupling. Each first section has a hard axis in a direction toward the main pole and is comprised of hcp-CoIr, dhcp-CoFe, a?-Fe—C, or NiAs-type Mn50Sb50 with a thickness from 50 to 500 nm. As a result, flux leakage from the main pole to a shield structure is reduced and area density is increased. A method for fabricating a composite shield structure is also provided.

Abstract: As the critical dimensions of liftoff patterns grow smaller, it becomes increasingly more difficult to make liftoff resists that have the required resolution. This problem has been overcome by use of a combination of ion beam processing and ozone slimming to form lift-off patterns with undercuts from a single layer of photoresist. The ion beam process serves to harden the top portion of the resist while the ozone is used to oxidize and erode the lower portion resist sidewall to form the undercut.

Abstract: A TAMR (Thermal Assisted Magnetic Recording) write head uses the energy of optical-laser generated plasmons in a plasmon antenna to locally heat a magnetic recording medium and reduce its coercivity and magnetic anisotropy. To enable the TAMR head to operate most effectively, the maximum gradient of the magnetic recording field should be concentrated in the small region being heated. Typically this does not occur because the spot being heated by the antenna is offset from the position at which the magnetic pole concentrates its magnetic field. The present invention incorporates a magnetic core within a plasmon antenna, so the antenna effectively becomes an extension of the magnetic pole and produces a magnetic field whose maximum gradient overlaps the region being heated by edge plasmons being generated in a conducting layer surrounding the antenna's magnetic core.

Abstract: A device to facilitate Thermally Assisted Magnetic Recording (TAMR), and a method for its manufacture, are described. One or more cylindrical lenses are used to focus light from a laser diode onto a wave-guide and a nearby plasmon antenna. Five embodiments of the invention are described, each one featuring a different way to couple the laser light to the optical wave-guide.