Abstract: A method, a non-transitory computer readable medium and a system for compensating for an electromagnetic interference induced deviation of an electron beam. The method may include obtaining measurement information about a magnetic field within an electron beam tool, the measurement information is generated by at least one planar Hall Effect magnetic sensor that is located within the electron beam tool; wherein the at least one planar Hall Effect magnetic sensor comprises at least one magnetometer integrated with at least one magnetic flux concentrator; estimating the electromagnetic interference induced deviation of the electron beam, the estimating is based on the magnetic field; and setting a trajectory of the electron beam to compensate for the electromagnetic interference induced deviation of the electron beam.

Abstract: The present disclosure generally relates to magnetic media devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The recording head includes a main pole, a trailing shield hot seed layer, a spin Hall layer disposed between the main pole and the trailing shield hot seed layer, and a spin-torque layer disposed between the main pole and the trailing shield hot seed layer. Spin-orbit torque (SOT) is generated from the spin Hall layer. The spin-torque layer magnetization switching or precession is induced by the SOT. The SOT based head reduces the switching current and the Vjump due to higher spin polarization ratio, which improves energy efficiency. In addition, the spin Hall layer and the spin-torque layer are easier to form compared to the conventional pseudo spin-valve structure.

Abstract: A magnetic recording head includes a trailing shield and a main pole. A trailing shield gap is between the trailing shield and the main pole. A spin orbital torque structure is within the trailing shield gap. The spin orbital torque structure includes a spin torque layer having a first side and a second side at a media facing surface. A first spin Hall layer is along the first side of the spin torque layer. A second spin Hall layer is along the second side of the spin torque layer. The first spin Hall layer comprises a heavy metal material having a positive spin Hall angle. The second spin Hall layer comprises a heavy metal material having a negative spin Hall angle.

Abstract: A MRAM memory cell comprises a SHE layer, a magnetic bit layer with perpendicular anisotropy and an Oersted layer. The magnetic bit layer has a switchable direction of magnetization in order to store data. Data is written to the MRAM memory cell using the Spin Hall Effect so that spin current generated in the SHE layer exerts a torque on the magnetic bit layer while the Oersted layer provides heat and an Oersted field to enable deterministic switching. Data is read form the MRAM memory cell using the Anomalous Hall Effect and sensing voltage at the Oersted layer.

Abstract: A magnetic recording head includes a trailing shield, a main pole, and a spin Hall layer. The spin Hall layer is disposed between the trailing shield and the main pole. A first spin torque layer is disposed between the spin Hall layer and the trailing shield. A second spin torque layer is disposed between the spin Hall layer and the main pole.

Abstract: A Spin Hall Effect (SHE) assisted magnetic recording device is disclosed wherein a stack of two SHE layers (SHE1 and SHE2) with an intermediate conductor layer is formed between a main pole (MP) trailing side and trailing shield (TS) bottom surface. SHE1 is a negative Spin Hall Angle (SHA) material while SHE2 is a positive SHA material. Current (Ia) flows from SHE1 across the conductor layer to SHE2. In one embodiment, spin polarized current in SHE1 applies spin transfer torque that tilts a local MP magnetization to a direction that enhances a MP write field, and spin polarized current in SHE2 generates spin transfer torque that tilts a local TS magnetization to a direction that increases the TS return field and improves bit error rate. In alternative embodiments, one of SHE1 and SHE2 is omitted so that only one of the MP write field and TS return field is enhanced.

Abstract: A spectrometer assembly is provided having an optical transmission filter including a stack of continuous, non-patterned alternating dielectric and metal layers. Angle-dependent transmission wavelength shift of the optical transmission filter with continuous metal layers is small e.g. in comparison with multilayer dielectric filters, facilitating size reduction of the spectrometer assembly.

Abstract: A spectrometer assembly is provided having an optical transmission filter including a stack of continuous, non-patterned alternating dielectric and metal layers. Angle-dependent transmission wavelength shift of the optical transmission filter with continuous metal layers is small e.g. in comparison with multilayer dielectric filters, facilitating size reduction of the spectrometer assembly.

Abstract: Embodiments described herein provide methods and apparatus for treating a magnetic substrate having an imprinted, oxygen-reactive mask formed thereon by implanting ions into a magnetically active surface of the magnetic substrate through the imprinted oxygen-reactive mask, wherein the ions do not reduce the oxygen reactivity of the mask, and removing the mask by exposing the substrate to an oxygen-containing plasma. The mask may be amorphous carbon, through which carbon-containing ions are implanted into the magnetically active surface. The carbon-containing ions, which may also contain hydrogen, may be formed by activating a mixture of hydrocarbon gas and hydrogen. A ratio of the hydrogen and the hydrocarbon gas may be selected or adjusted to control the ion implantation.

Abstract: The present disclosure generally relates to data storage devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The head includes a main pole, a trailing shield, and an oscillator located between the main pole and the trailing shield. The oscillator is disposed at a media facing surface (MFS). The oscillator includes a spin-torque layer sandwiched between two distinct spin Hall layers. The two distinct spin Hall layers generate spin-orbit torque (SOT) that induces in-plane precessions on opposite surfaces of the spin-torque layer, and both in-plane precessions are in the same direction. The same-direction in-plane precessions on opposite surfaces of the spin-torque layer reduce the critical current of the oscillation of the oscillator, leading to high quality recording.

Abstract: In various embodiments, a magnetic medium may be provided. The magnetic medium may include a substrate. The substrate may include a servo layer over the substrate. The servo layer may include a cap layer having a first coercivity. The servo layer may also include a granular layer having a second coercivity greater than the first coercivity. The servo layer may also include an intervening layer between the cap layer and the granular layer.

Abstract: The present disclosure generally relates to data storage devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The head includes a main pole, a spin-torque structure surrounding at least a portion of the main pole at a media facing surface (MFS), and a spin Hall structure surrounding the spin-torque structure. Strong spin-orbit torque (SOT) is generated from the spin Hall structure, enforcing in-plane magnetization oscillation in the spin-torque structure. The SOT based head with the spin Hall structure surrounding the spin-torque structure utilizes less current flowed to the spin Hall structure due to the strong SOT generated by the spin Hall structure.

Abstract: Embodiments relate to vertical Hall effect devices comprising Hall effect structures with three contacts in each Hall effect region. In one embodiment, the contacts are interconnected with terminals such that the Hall effect device has symmetry and nominally identical internal resistances in the absence of externally applied magnetic fields. Embodiments are capable of operating in multiple operating phases, such that spinning can be used to measure field redundantly and improve magnetic field measurement accuracy.

Abstract: A structure includes an air bearing surface including a plurality of material layers arranged in at least one dimension on the air bearing surface. The structure further includes a microelectronic device and a resistive heating element, which each include at least one of the plurality of material layers. The resistive heating element is electrically isolated from the microelectronic device. The microelectronic device is heated by said resistive heating element. Optionally, a structure includes a tape reader or a tape writer, located at an air bearing surface. A resistive heating element is electrically isolated from the tape reader or writer and heats the tape reader or the tape writer. Optionally, a method includes identifying a microelectronic device located at an air bearing surface, identifying a resistive heating element, which is electrically isolated from the microelectronic device, applying a bias current through the resistive heating element to heat the microelectronic device.

Abstract: An embodiment of an integrated electronic device having a body, made at least partially of semiconductor material and having a top surface, a bottom surface, and a side surface, and a first antenna, which is integrated in the body and enables magnetic or electromagnetic coupling of the integrated electronic device with a further antenna. The integrated electronic device moreover has a coupling region made of magnetic material, which provides, in use, a communication channel between the first antenna and the further antenna.

Abstract: A structure includes an air bearing surface including a plurality of material layers arranged in at least one dimension on the air bearing surface. The structure further includes a microelectronic device and a resistive heating element, which each include at least one of the plurality of material layers. The resistive heating element is electrically isolated from the microelectronic device. The microelectronic device is heated by said resistive heating element. Optionally, a structure includes a tape reader or a tape writer, located at an air bearing surface. A resistive heating element is electrically isolated from the tape reader or writer and heats the tape reader or the tape writer. Optionally, a method includes identifying a microelectronic device located at an air bearing surface, identifying a resistive heating element, which is electrically isolated from the microelectronic device, applying a bias current through the resistive heating element to heat the microelectronic device.

Abstract: A method includes identifying a microelectronic device located at an air bearing surface. The method further includes identifying a resistive heating element electrically isolated the said microelectronic device; applying a bias current through the resistive heating element to generate localized heat to heat the microelectronic device; identifying a predetermined humidity threshold and a separation distance between the microelectronic device and the resistive heating element in at least one dimension; measuring an ambient temperature at the air bearing surface; measuring an ambient relative humidity at the air bearing surface; determining an effective temperature; and adjusting the bias current to heat the microelectronic device to the effective temperature. The resistive heating element is one of a plurality, and at least two of the plurality of resistive heating elements are powered from a common source such that at least two of the resistive heating elements are commonly controllable via a common source.

Abstract: Embodiments described herein provide methods and apparatus for treating a magnetic substrate having an imprinted, oxygen-reactive mask formed thereon by implanting ions into a magnetically active surface of the magnetic substrate through the imprinted oxygen-reactive mask, wherein the ions do not reduce the oxygen reactivity of the mask, and removing the mask by exposing the substrate to an oxygen-containing plasma. The mask may be amorphous carbon, through which carbon-containing ions are implanted into the magnetically active surface. The carbon-containing ions, which may also contain hydrogen, may be formed by activating a mixture of hydrocarbon gas and hydrogen. A ratio of the hydrogen and the hydrocarbon gas may be selected or adjusted to control the ion implantation.

Abstract: A system comprising a sensor with a free layer that exhibits an anomalous Hall effect is disclosed. Further, the sensor has a magnetic underlayer below the free layer in a track direction for biasing a magnetic orientation of the free layer in a first magnetic orientation, and a magnetic overlayer above the free layer in the track direction for biasing the magnetic orientation of the free layer in the first magnetic orientation. Still further, the sensor has a lower nonmagnetic spacer layer between the magnetic underlayer and the free layer, and an upper nonmagnetic spacer layer between the magnetic overlayer and the free layer.

Abstract: A data reader may be configured at least with detector and injector stacks that each has a common spin accumulation layer. The detector stack may positioned on an air bearing surface (ABS) while the injector stack is positioned distal the ABS. The injector stack can have a diffusive layer with a larger spin diffusion length than mean free path.

Abstract: The present invention relates to a magnetic sensor that provides the sensitivity adjustment on a wafer and that has a superior mass productiveness and a small characteristic variation. The magnetic sensor includes a magnetic sensitive portion provided on a substrate that is made of a compound semiconductor and that has a cross-shaped pattern. This magnetic sensitive portion includes input terminals and output terminals. At least one of input terminals of the input terminal is series-connected to a trimming portion having a compound semiconductor via a connection electrode. By performing laser trimming on the trimming portion series-connected via the connection electrode to the magnetic sensitive portion while performing a wafer probing (electric test), the adjustment of the constant voltage sensitivity is provided.

Abstract: A motor includes a rotor, a sensor unit, an offset unit, a rectification unit and a modulating unit. The sensor unit outputs a first signal in accordance with a magnetic field variation of the rotor. The offset unit is coupled to the sensor unit, and outputs a second signal in accordance with the first signal. The rectification unit is coupled to the offset unit, and outputs a third signal in accordance with the second signal. The modulating unit is coupled to the rectification unit, and outputs a control signal in accordance with a result by comparing the third signal with a periodic signal. The modulating unit controls a reverse rotation of the rotor smoothly in accordance with the control signal. A control method of the motor is also disclosed.

Abstract: A magnetic sensor utilizing the spin Hall effect to polarize electrons for use in measuring a magnetic field. The sensor eliminates the need for a pinned layer structure or antiferromagnetic layer (AFM layer), thereby reducing gap thickness for increased data density. The sensor includes a non-magnetic, electrically conductive layer that is configured to accumulate electrons predominantly of one spin at a side thereof when a current flows there-through. A magnetic free layer is located adjacent to the side of the non-magnetic, electrically conductive layer. A change in the direction of magnetization in the free layer relative to the orientation of the spin polarized electrons causes a change in voltage output of the sensor.

Abstract: In one embodiment a magnetic head includes a sensor thin film adapted for producing a planar Hall voltage, the sensor thin film having a thickness along a down-track direction that is greater than a thickness along a cross-track direction. The down-track direction is in a direction of travel of a magnetic medium relative to the sensor thin film, and the cross-track direction is perpendicular to the down-track direction. In another embodiment, at least one magnetic head as described above is included in a magnetic data storage system, which includes a magnetic medium, a drive mechanism for passing the magnetic medium over the at least one magnetic head, and a controller electrically coupled to the at least one magnetic head for controlling operation of the at least one magnetic head. Other heads and systems are described according to various other embodiments.

Abstract: A device for sensing a magnetic field is described. The device comprises first, second and third leads and a junction between the leads. The junction and leads are arranged in a plane and the junction is configured to exhibit quantum confinement in a direction perpendicular to the plane. The first lead is arranged on one side of the junction and the second and third leads are arranged on an opposite side of the junction. The first lead is configured to limit angle of spread of charge carriers entering the junction so that, when charge carriers flow into the junction from the first lead, the charge carriers form a substantially nondivergent beam.

Abstract: An apparatus for sensing magnetic domains in a patterned media that includes a first sensing element and a second sensing element in electrical communication with the first sensing element. The first sensing element has an output voltage lead and the second sensing element has an output voltage lead. The patterned media may be a bit patterned media or a track patterned media.

Abstract: According to one embodiment, magnetic reproducing element for detecting a magnetic field from a magnetic recording medium comprises a sensor film including a perpendicular magnetization film having a magnetization easy axis in a direction perpendicular to a film plane, wherein magnetization in the sensor film tilts upward or downward in an element height direction from the magnetization easy axis while no magnetic field is applied from the magnetic recording medium, and change in anomalous Hall voltage generated in the sensor film is detected, thereby allowing the magnetic field applied from the magnetic recording medium to be detected. Other magnetic reproducing elements and magnetic heads employing magnetic reproducing elements are described as well.

Abstract: A magnetic sensor reduces thermal fluctuation and realizes high-sensitive signal detection using a spin Hall device of a simple structure configured with only one magnetic layer. The magnetic sensor includes a stacked film in which a nonmagnetic spin Hall layer, a nonmagnetic insulator layer, and a magnetic layer are stacked, an electrode nonmagnetic terminal pair connected to a side surface of the nonmagnetic spin Hall layer, and a unit applying a current in a film thickness direction of the stacked film. A thickness of the nonmagnetic spin Hall layer is thinner than twice a spin diffusion length of a material constituting the nonmagnetic spin Hall layer. A magnetization direction of the magnetic layer magnetized by an external magnetic field is detected due to the polarity of a voltage across both ends of the electrode nonmagnetic terminal pair.

Abstract: A wire rope tester including a magnetic testing device; the wire rope tester includes a Remote Data Recorder mounted on a sensor head of the magnetic testing device.

Abstract: In one embodiment a magnetic head includes a sensor thin film adapted for producing a planar Hall voltage, the sensor thin film having a thickness along a down-track direction that is greater than a thickness along a cross-track direction. The down-track direction is in a direction of travel of a magnetic medium relative to the sensor thin film, and the cross-track direction is perpendicular to the down-track direction. In another embodiment, at least one magnetic head as described above is included in a magnetic data storage system, which includes a magnetic medium, a drive mechanism for passing the magnetic medium over the at least one magnetic head, and a controller electrically coupled to the at least one magnetic head for controlling operation of the at least one magnetic head. Other heads and systems are described according to various other embodiments.

Abstract: An electric field read/write head, a method of manufacturing the same, and an information storage device including the electric field read/write head are provided. The electric field read/write head includes: a resistance region formed in a substrate which comprises an end surface facing a recording medium; a source and a drain formed in the substrate and disposed on both sides of the resistance region, respectively; and an insulating layer and a write electrode formed sequentially on the resistance region, wherein the length (l) to width (w) ratio (l/w) of the resistance region satisfies (l/w)?0.2.

Abstract: A Lorenz magnetoresistive sensor having a pair of voltage leads and a pair of current leads. The voltage leads are located at either side of one of the current leads and are separated by a distance that is substantially equal to the length of a bit to be measured. The Lorenz magnetoresistive sensor can be, for example an extraordinary magnetoresistive sensor having a quantum well structure such as a two dimensional electron gas and a shunt structure formed on an edge of the quantum well structure opposite the voltage and current leads.

Abstract: The present invention is directed to the use of perovskite manganite thin films and other magnetic films that exhibit both planar Hall effect and biaxial magnetic anisotropy to form the active area in magnetic sensor devices and in magnetic bit cells used in magnetoresistive random access memory (MRAM) devices. The manganite thin films of the invention are ferromagnetic manganites of the formula R1-xAxMnO3, wherein R is a rare-earth metal, A is an alkaline earth metal, and x is generally between about 0.15 and about 0.5.

Abstract: According to one embodiment, magnetic reproducing element for detecting a magnetic field from a magnetic recording medium comprises a sensor film including a perpendicular magnetization film having a magnetization easy axis in a direction perpendicular to a film plane, wherein magnetization in the sensor film tilts upward or downward in an element height direction from the magnetization easy axis while no magnetic field is applied from the magnetic recording medium, and change in anomalous Hall voltage generated in the sensor film is detected, thereby allowing the magnetic field applied from the magnetic recording medium to be detected. Other magnetic reproducing elements and magnetic heads employing magnetic reproducing elements are described as well.

Abstract: An apparatus for sensing magnetic domains in a patterned media that includes a first sensing element and a second sensing element in electrical communication with the first sensing element. The first sensing element has an output voltage lead and the second sensing element has an output voltage lead. The patterned media may be a bit patterned media or a track patterned media.

Abstract: A magnetic field sensor includes a metallic bar coupled to a substrate. Current leads are adapted to provide current to the ferromagnetic bar. Voltage leads are coupled to the ferromagnetic bar to sense an induced Hall voltage therein.

Abstract: An electric field effect read/write head for recording/reproducing information on/from a ferroelectric recording medium using an electric field effect includes a semiconductor substrate, a recess portion formed in an upper surface of the semiconductor substrate facing the ferroelectric recording medium, and a recording/reproduction portion provided in the recess portion.

Abstract: An Extraordinary Magnetoresistive Sensor (EMR Sensor) having wide voltage lead tabs for reduced noise and increased signal to noise ratio. The leads can be formed in a triad structure, wherein a pair of voltage leads is located at either side of a current lead, or can be formed in a diad structure having a single voltage lead located at one side of a current lead.

Abstract: A magnetic field sensor, including an insulating substrate and a conductive thin film deposited on the substrate. The thin film consists of a material having an extraordinary Hall coefficient, the thin film also has a resistivity and a film thickness no greater. than a threshold thickness at which the resistivity is substantially equal to 150% of a bulk resistivity of the material. The sensor also includes conductors coupled to the thin film for injecting a current into the film and measuring a voltage generated across the thin film responsive to the injected current. Devices having other types of thin films, including homogeneous and non-homogeneous films, the films having enhanced extraordinary Hall coefficients, are also provided.

Abstract: A magnetic head has a sensor which employs the “Hall effect”. In one illustrative example, the sensor includes a generally planar body made of a semiconductor heterostructure; first and second contacts comprising first and second drains, respectively, which are formed over a first end of the body and spaced equally apart from a centerline of the body; and a third contact comprising a source formed over a second end of the body which is opposite the first end of the body. The semiconductor heterostructure is comprised of a high mobility two-dimensional electron or hole gas close to an air bearing surface (ABS) of the magnetic head so as to be exposed to magnetic field lines substantially normal to it from magnetically recorded bits. Advantageously, the sensor does not require magnetic materials utilized in conventional sensors and therefore does not suffer from magnetic noise associated therewith.

Abstract: An article is formed as a substrate having a projection extending outwardly therefrom. The article may be a magnetic recording head and the projection a write pole. The projection has a width in a thinnest dimension measured parallel to a substrate surface of no more than about 0.3 micrometers and a height measured perpendicular to the substrate of not less than about 5 times the width. The article is fabricated by forming an overlying structure on the substrate with an edge thereon, depositing a replication layer lying on the edge, depositing a filler onto the edge and the substrate, so that the filler, the replication layer, and the overlying structure in combination comprise a continuous layer on the substrate, selectively removing at least a portion of the replication layer from a free surface of the continuous layer inwardly toward the substrate, to form a defined cavity, and depositing a projection material into the defined cavity to form the projection.

Abstract: A magnetic head includes a first electrode layer, a first ferromagnetic electrode pair that is electrically connected to the first electrode layer, and a second ferromagnetic electrode pair that intersects with a current which flows between the first ferromagnetic electrode pairs and is electrically connected with the first electrode layer. The current is allowed to flow between the first ferromagnetic electrode pair through the first electrode layer to accumulate spin electrons in the first electrode layer. A direction of magnetization of the fourth ferromagnetic electrode layer changes upon application of an external magnetic field. The second ferromagnetic electrode pair is so arranged as to intersect with the current that flows between the first ferromagnetic electrode pair, to increase a rate of change in the output signal of the in-plane spin accumulation effect.

Abstract: A magnetic field sensor, including an insulating substrate and a conductive thin film deposited on the substrate. The thin film consists of a material having an extraordinary Hall coefficient, the thin film also has a resistivity and a film thickness no greater than a threshold thickness at which the resistivity is substantially equal to 150% of a bulk resistivity of the material. The sensor also includes conductors coupled to the thin film for injecting a current into the film and measuring a voltage generated across the thin film responsive to the injected current. Devices having other types of thin films, including homogeneous and non-homogeneous films, the films having enhanced extraordinary Hall coefficients, are also provided.

Abstract: A magnetic field sensor for sensing an applied magnetic field by utilizing a Hall effect. Used, as a sensor portion, are compound materials such as FeN showing a significant anomalous Hall effect, and materials containing magnetic properties such as a magnetic semiconductor having a zincblende structure and oxide having a perovskite structure. A device structure of the magnetic field sensor is adopted, in which by providing a current terminal to a film and a voltage terminal thereof respectively in a film thickness direction and in an in-plane direction, the magnetic field can be guided into the in-plane direction.

Abstract: A magnetic read head comprises a magnetic sensor mounted on a back surface of a slider, wherein the magnetic sensor includes a nonmagnetic member, a conductive shunt positioned adjacent to the nonmagnetic member, a first conductor electrically connected to the nonmagnetic member, and a second conductor electrically connected to the nonmagnetic member. Magnetic sensors comprising a nonmagnetic member including a material selected from the group consisting of: Bi, Sb and As, and alloys of Bi, Sb and As; a shunt conductor positioned adjacent to the nonmagnetic member; a first conductor electrically connected to the nonmagnetic member; and a second conductor electrically connected to the nonmagnetic member are also provided. Disc drives that include the read heads and sensors are also included.

Abstract: A magnetic field sensor for sensing an applied magnetic field by utilizing a Hall effect. Used, as a sensor portion, are compound materials such as FeN showing a significant anomalous Hall effect, and materials containing magnetic properties such as a magnetic semiconductor having a zincblende structure and oxide having a perovskite structure. A device structure of the magnetic field sensor is adopted, in which by providing a current terminal to a film and a voltage terminal thereof respectively in a film thickness direction and in an in-plane direction, the magnetic field can be guided into the in-plane direction.

Abstract: A vertical Hall sensor includes a semiconductor crystal with three or more arm sections that are arranged at a uniform angle distance to each other. A central electrode and external current electrodes are arranged on the surface of the sensor, and a plurality of Hall voltage contacts is arranged therebetween. The semiconductor crystal is thick enough for a current flow to pass between the electrodes in each arm section of the semiconductor crystal, whereby the current flow produces several sensitivities in the Hall sensor corresponding to the number of arm sections with a correspondingly predefined angular dependency for a magnetic field that is directed in a parallel position with respect to the surface. The Hall voltages, which can be produced using one such multi-arm vertical Hall sensor, can be used in a reinforced and direct manner as an output signal for an electric motor.

Abstract: Disclosed is a magnetic field sensor for sensing an applied magnetic field by utilizing a Hall effect. As a sensor portion, used are compound materials such as FeN showing a significant anomalous Hall effect, and materials containing magnetic such as a magnetic semiconductor having a zincblende structure and oxide having a perovskite structure. A device structure of the magnetic field sensor is adopted, in which by providing a current terminal of a film and a voltage terminal thereof respectively in a film thickness direction and in an in-plane direction, the magnetic field can be guided into the in-plane direction.

Abstract: A timepiece, whose hands move by mechanical energy of a mainspring transmitted through a wheel train, includes a winding-up portion for accumulating energy in the mainspring, an addition and subtraction wheel train driven by addition and subtraction of accumulated energy corresponding to an amount by which the mainspring is wound up and unwound, respectively, an addition and subtraction wheel, disposed in the addition and subtraction wheel train, that rotates in correspondence with an amount by which the mainspring is wound up and unwound, and a lock mechanism actuated in response to the rotation of the addition and subtraction wheel to limit winding up and unwinding of the mainspring to a selected range of windings of the mainspring. This controls the torque output by the mainspring to a fixed range. The addition and subtraction wheel train allows efficient use of space, and can be incorporated in a watch.

Abstract: A glide test head assembly optimized for glide avalanche testing. The glide test head assembly of the present invention includes air bearing surfaces formed with a negative crown, or slightly concave surface. The negative crown of the air bearing surfaces of the inventive glide test head lowers the hydrodynamic pressure between the glide test head assembly and a spinning disc for given disc rotational speeds, enabling the glide test head assembly to fly at a lower heights at a greater linear velocity, and thus with increased stability. The increased flying stability of the inventive glide test head assembly improves the correlation between true flying height and disc/head contact detection for glide avalanche testing.