The Experts below are selected from a list of 41634 Experts worldwide ranked by ideXlab platform
Stephen Y Chou - One of the best experts on this subject based on the ideXlab platform.
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nanolithographically defined Magnetic structures and quantum Magnetic Disk invited
Journal of Applied Physics, 1996Co-Authors: Stephen Y Chou, Peter R. Krauss, Linshu KongAbstract:Isolated and interactive arrays of Magnetic nanostructures as small as 15 nm are fabricated using nanolithography and related technologies, and are characterized using Magnetic force microscopy. It has been demonstrated that manipulating the size, aspect ratio, and spacing of these nanostructures can lead to unique control of their Magnetic properties. A quantum Magnetic Disk based on discrete single‐domain nanoMagnetic structures with storage density of 65 Gbits/in.2 is demonstrated along with a low‐cost method for mass producing such Disks. Other impacts that nanofabrication can bring to the development of future Magnetic storage are discussed.
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fabrication of planar quantum Magnetic Disk structure using electron beam lithography reactive ion etching and chemical mechanical polishing
Journal of Vacuum Science & Technology B, 1995Co-Authors: Peter R. Krauss, Stephen Y ChouAbstract:A planar quantum Magnetic Disk (QMD) with a Magnetic storage density of 65 Gbit/in.2, over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density, has been fabricated. The planar QMD structure consists of single‐domain nickel (Magnetic) nanopillars uniformly embedded in a SiO2 (nonMagnetic) Disk. Electron beam lithography was used to define the QMD bit’s size and location, and reactive ion etching was used to form an SiO2 template. Nickel electroplating was used to selectively deposit nickel into the template openings, and chemical mechanical polishing was used to planarize the surface. The resulting QMD consists of ultrahigh density arrays of single‐domain Magnetic pillars with a 50 nm diameter and 100 nm period uniformly embedded in 200‐nm‐thick SiO2 and with a surface roughness of 0.5 nm root mean square. Each single‐domain structure has a quantized Magnetic moment and acts as a single bit to store one bit of binary information. Furthermore, a method for mass production of Q...
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single domain Magnetic pillar array of 35 nm diameter and 65 gbits in 2 density for ultrahigh density quantum Magnetic storage
Journal of Applied Physics, 1994Co-Authors: Stephen Y Chou, Mark S. Wei, Peter R. Krauss, Paul B. FischerAbstract:Using electron beam nanolithography and electroplating, arrays of Ni pillars on silicon that have a uniform diameter of 35 nm, a height of 120 nm, and a period of 100 nm were fabricated. The density of the pillar arrays is 65 Gbits/in.2—over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density. Because of their nanoscale size, shape anisotropy, and separation from each other, each Ni pillar is single domain with only two quantized perpendicular magnetization states: up and down. Each pillar can be used to store one bit of information, therefore such nanoMagnetic pillar array storage offers a rather different paradigm than the conventional storage method. A quantum Magnetic Disk scheme that is based on uniformly embedding single‐domain Magnetic structures in a nonMagnetic Disk is proposed.
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study of nanoscale Magnetic structures fabricated using electron beam lithography and quantum Magnetic Disk
Journal of Vacuum Science & Technology B, 1994Co-Authors: Stephen Y Chou, Mark S. Wei, Peter R. Krauss, Paul B. FischerAbstract:Two types of nanoscale single‐domain Magnetic structures were fabricated using e‐beam nanolithography and were studied using Magnetic force microscopy. The first structure is the isolated and interactive arrays of Ni bars on silicon that are 35 nm thick, 1 μm long, and have widths ranging from 15 to 200 nm and spacings ranging from 200 to 600 nm. The second structure is an array of Ni pillars on silicon that have a uniform diameter of 35 nm, a height of 120 nm, and a density of 65 Gbits/in2—over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density. It was found that the Magnetic properties of these structures can be controlled by engineering their size and spacing. When the bar width is smaller than 150 nm, the bars become single Magnetic domain. As the width of the isolated bars decreased from 200 to 55 nm, the Magnetic field needed to switch the magnetization of these bars increased monotonically from 100 to 740 Oe which is the highest field reported for Ni. However, furthe...
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study of nanoscale Magnetic structures fabricated using electron beam lithography and quantum Magnetic Disk
Journal of Vacuum Science & Technology B, 1994Co-Authors: Stephen Y Chou, Mark S. Wei, Peter R. Krauss, Paul B. FischerAbstract:Two types of nanoscale single‐domain Magnetic structures were fabricated using e‐beam nanolithography and were studied using Magnetic force microscopy. The first structure is the isolated and interactive arrays of Ni bars on silicon that are 35 nm thick, 1 μm long, and have widths ranging from 15 to 200 nm and spacings ranging from 200 to 600 nm. The second structure is an array of Ni pillars on silicon that have a uniform diameter of 35 nm, a height of 120 nm, and a density of 65 Gbits/in2—over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density. It was found that the Magnetic properties of these structures can be controlled by engineering their size and spacing. When the bar width is smaller than 150 nm, the bars become single Magnetic domain. As the width of the isolated bars decreased from 200 to 55 nm, the Magnetic field needed to switch the magnetization of these bars increased monotonically from 100 to 740 Oe which is the highest field reported for Ni. However, further reduction of bar width led the switching field to decrease due to thermal effect. Furthermore, it was found that as the bar spacings become smaller, the interaction between the bars will reduce the switching field. Finally, based on the artificially patterned single‐domain Magnetic structures, we propose a new paradigm for ultra‐high‐density Magnetic recording media: quantum Magnetic Disk.
Yu Jen Wang - One of the best experts on this subject based on the ideXlab platform.
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Design of a weighted-rotor energy harvester based on dynamic analysis and optimization of circular halbach array Magnetic Disk
Micromachines, 2015Co-Authors: Yu Jen Wang, Yu Ti Hao, Hao Yu LinAbstract:This paper proposes the design of a weighted-rotor energy harvester (WREH) in which the oscillation is caused by the periodic change of the tangential component of gravity, to harvest kinetic energy from a rotating wheel. When a WREH is designed with a suitable characteristic length, the rotor’s natural frequency changes according to the wheel rotation speed and the rotor oscillates at a wide angle and high angular velocity to generate a large amount of power. The Magnetic Disk is designed according to an optimized circular Halbach array. The optimized circular Halbach array Magnetic Disk provides the largest induced EMF for different sector-angle ratios for the same Magnetic Disk volume. This study examined the output voltage and power by considering the constant and accelerating plate-rotation speeds, respectively. This paper discusses the effects of the angular acceleration speed of a rotating wheel corresponding to the dynamic behaviors of a weighted rotor. The average output power is 399 to 535 microwatts at plate-rotation speeds from 300 to 500 rpm, enabling the WREH to be a suitable power source for a tire-pressure monitoring system.
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natural frequency self tuning energy harvester using a circular halbach array Magnetic Disk
Journal of Intelligent Material Systems and Structures, 2012Co-Authors: Chung De Chen, Cheng-kuo Sung, Yu Jen Wang, Chien LiAbstract:A novel natural frequency self-tuning energy harvester is presented, which utilizes the presence of the nonlinearity model and the well-weighted swing Disk to maximize the power output and the frequency bandwidth for a wheel rotating at any speed. Kinetic energy harvesters are frequency selective, meaning that they have high power transmission efficiency only when they are excited at their natural frequency. The well-weighted swing Disk with nonlinear effects can render the energy harvester more broadband, that is, it has a more steady power generation at various wheel speeds than the ill-weighted swing Disk has. We integrate magnets in a novel circular Halbach array and coils into the design to augment the Magnetic strength on one side of the array where the coils are placed. Therefore, the gradient of the average Magnetic flux density for the circular Halbach array Disk is larger than that of the multipolar Magnetic Disk. The dynamic models with electromechanical couplings have been established and are ...
Paul B. Fischer - One of the best experts on this subject based on the ideXlab platform.
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single domain Magnetic pillar array of 35 nm diameter and 65 gbits in 2 density for ultrahigh density quantum Magnetic storage
Journal of Applied Physics, 1994Co-Authors: Stephen Y Chou, Mark S. Wei, Peter R. Krauss, Paul B. FischerAbstract:Using electron beam nanolithography and electroplating, arrays of Ni pillars on silicon that have a uniform diameter of 35 nm, a height of 120 nm, and a period of 100 nm were fabricated. The density of the pillar arrays is 65 Gbits/in.2—over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density. Because of their nanoscale size, shape anisotropy, and separation from each other, each Ni pillar is single domain with only two quantized perpendicular magnetization states: up and down. Each pillar can be used to store one bit of information, therefore such nanoMagnetic pillar array storage offers a rather different paradigm than the conventional storage method. A quantum Magnetic Disk scheme that is based on uniformly embedding single‐domain Magnetic structures in a nonMagnetic Disk is proposed.
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study of nanoscale Magnetic structures fabricated using electron beam lithography and quantum Magnetic Disk
Journal of Vacuum Science & Technology B, 1994Co-Authors: Stephen Y Chou, Mark S. Wei, Peter R. Krauss, Paul B. FischerAbstract:Two types of nanoscale single‐domain Magnetic structures were fabricated using e‐beam nanolithography and were studied using Magnetic force microscopy. The first structure is the isolated and interactive arrays of Ni bars on silicon that are 35 nm thick, 1 μm long, and have widths ranging from 15 to 200 nm and spacings ranging from 200 to 600 nm. The second structure is an array of Ni pillars on silicon that have a uniform diameter of 35 nm, a height of 120 nm, and a density of 65 Gbits/in2—over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density. It was found that the Magnetic properties of these structures can be controlled by engineering their size and spacing. When the bar width is smaller than 150 nm, the bars become single Magnetic domain. As the width of the isolated bars decreased from 200 to 55 nm, the Magnetic field needed to switch the magnetization of these bars increased monotonically from 100 to 740 Oe which is the highest field reported for Ni. However, furthe...
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study of nanoscale Magnetic structures fabricated using electron beam lithography and quantum Magnetic Disk
Journal of Vacuum Science & Technology B, 1994Co-Authors: Stephen Y Chou, Mark S. Wei, Peter R. Krauss, Paul B. FischerAbstract:Two types of nanoscale single‐domain Magnetic structures were fabricated using e‐beam nanolithography and were studied using Magnetic force microscopy. The first structure is the isolated and interactive arrays of Ni bars on silicon that are 35 nm thick, 1 μm long, and have widths ranging from 15 to 200 nm and spacings ranging from 200 to 600 nm. The second structure is an array of Ni pillars on silicon that have a uniform diameter of 35 nm, a height of 120 nm, and a density of 65 Gbits/in2—over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density. It was found that the Magnetic properties of these structures can be controlled by engineering their size and spacing. When the bar width is smaller than 150 nm, the bars become single Magnetic domain. As the width of the isolated bars decreased from 200 to 55 nm, the Magnetic field needed to switch the magnetization of these bars increased monotonically from 100 to 740 Oe which is the highest field reported for Ni. However, further reduction of bar width led the switching field to decrease due to thermal effect. Furthermore, it was found that as the bar spacings become smaller, the interaction between the bars will reduce the switching field. Finally, based on the artificially patterned single‐domain Magnetic structures, we propose a new paradigm for ultra‐high‐density Magnetic recording media: quantum Magnetic Disk.
Peter R. Krauss - One of the best experts on this subject based on the ideXlab platform.
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nanolithographically defined Magnetic structures and quantum Magnetic Disk invited
Journal of Applied Physics, 1996Co-Authors: Stephen Y Chou, Peter R. Krauss, Linshu KongAbstract:Isolated and interactive arrays of Magnetic nanostructures as small as 15 nm are fabricated using nanolithography and related technologies, and are characterized using Magnetic force microscopy. It has been demonstrated that manipulating the size, aspect ratio, and spacing of these nanostructures can lead to unique control of their Magnetic properties. A quantum Magnetic Disk based on discrete single‐domain nanoMagnetic structures with storage density of 65 Gbits/in.2 is demonstrated along with a low‐cost method for mass producing such Disks. Other impacts that nanofabrication can bring to the development of future Magnetic storage are discussed.
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fabrication of planar quantum Magnetic Disk structure using electron beam lithography reactive ion etching and chemical mechanical polishing
Journal of Vacuum Science & Technology B, 1995Co-Authors: Peter R. Krauss, Stephen Y ChouAbstract:A planar quantum Magnetic Disk (QMD) with a Magnetic storage density of 65 Gbit/in.2, over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density, has been fabricated. The planar QMD structure consists of single‐domain nickel (Magnetic) nanopillars uniformly embedded in a SiO2 (nonMagnetic) Disk. Electron beam lithography was used to define the QMD bit’s size and location, and reactive ion etching was used to form an SiO2 template. Nickel electroplating was used to selectively deposit nickel into the template openings, and chemical mechanical polishing was used to planarize the surface. The resulting QMD consists of ultrahigh density arrays of single‐domain Magnetic pillars with a 50 nm diameter and 100 nm period uniformly embedded in 200‐nm‐thick SiO2 and with a surface roughness of 0.5 nm root mean square. Each single‐domain structure has a quantized Magnetic moment and acts as a single bit to store one bit of binary information. Furthermore, a method for mass production of Q...
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single domain Magnetic pillar array of 35 nm diameter and 65 gbits in 2 density for ultrahigh density quantum Magnetic storage
Journal of Applied Physics, 1994Co-Authors: Stephen Y Chou, Mark S. Wei, Peter R. Krauss, Paul B. FischerAbstract:Using electron beam nanolithography and electroplating, arrays of Ni pillars on silicon that have a uniform diameter of 35 nm, a height of 120 nm, and a period of 100 nm were fabricated. The density of the pillar arrays is 65 Gbits/in.2—over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density. Because of their nanoscale size, shape anisotropy, and separation from each other, each Ni pillar is single domain with only two quantized perpendicular magnetization states: up and down. Each pillar can be used to store one bit of information, therefore such nanoMagnetic pillar array storage offers a rather different paradigm than the conventional storage method. A quantum Magnetic Disk scheme that is based on uniformly embedding single‐domain Magnetic structures in a nonMagnetic Disk is proposed.
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study of nanoscale Magnetic structures fabricated using electron beam lithography and quantum Magnetic Disk
Journal of Vacuum Science & Technology B, 1994Co-Authors: Stephen Y Chou, Mark S. Wei, Peter R. Krauss, Paul B. FischerAbstract:Two types of nanoscale single‐domain Magnetic structures were fabricated using e‐beam nanolithography and were studied using Magnetic force microscopy. The first structure is the isolated and interactive arrays of Ni bars on silicon that are 35 nm thick, 1 μm long, and have widths ranging from 15 to 200 nm and spacings ranging from 200 to 600 nm. The second structure is an array of Ni pillars on silicon that have a uniform diameter of 35 nm, a height of 120 nm, and a density of 65 Gbits/in2—over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density. It was found that the Magnetic properties of these structures can be controlled by engineering their size and spacing. When the bar width is smaller than 150 nm, the bars become single Magnetic domain. As the width of the isolated bars decreased from 200 to 55 nm, the Magnetic field needed to switch the magnetization of these bars increased monotonically from 100 to 740 Oe which is the highest field reported for Ni. However, furthe...
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study of nanoscale Magnetic structures fabricated using electron beam lithography and quantum Magnetic Disk
Journal of Vacuum Science & Technology B, 1994Co-Authors: Stephen Y Chou, Mark S. Wei, Peter R. Krauss, Paul B. FischerAbstract:Two types of nanoscale single‐domain Magnetic structures were fabricated using e‐beam nanolithography and were studied using Magnetic force microscopy. The first structure is the isolated and interactive arrays of Ni bars on silicon that are 35 nm thick, 1 μm long, and have widths ranging from 15 to 200 nm and spacings ranging from 200 to 600 nm. The second structure is an array of Ni pillars on silicon that have a uniform diameter of 35 nm, a height of 120 nm, and a density of 65 Gbits/in2—over two orders of magnitude greater than the state‐of‐the‐art Magnetic storage density. It was found that the Magnetic properties of these structures can be controlled by engineering their size and spacing. When the bar width is smaller than 150 nm, the bars become single Magnetic domain. As the width of the isolated bars decreased from 200 to 55 nm, the Magnetic field needed to switch the magnetization of these bars increased monotonically from 100 to 740 Oe which is the highest field reported for Ni. However, further reduction of bar width led the switching field to decrease due to thermal effect. Furthermore, it was found that as the bar spacings become smaller, the interaction between the bars will reduce the switching field. Finally, based on the artificially patterned single‐domain Magnetic structures, we propose a new paradigm for ultra‐high‐density Magnetic recording media: quantum Magnetic Disk.
Masayoshi Tomizuka - One of the best experts on this subject based on the ideXlab platform.
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improved track following in Magnetic Disk drives using a disturbance observer
IEEE-ASME Transactions on Mechatronics, 2000Co-Authors: M T White, Masayoshi Tomizuka, C SmithAbstract:Improving the position control of the Disk drive read/write heads is an important step in increasing the storage capacity of a drive, especially in the presence of internal and external disturbances. To address this problem, the typical feedback loop of a Disk drive servo system was augmented with a disturbance observer. The disturbance observer uses the position error signal and a nominal model of the plant to create an estimate of the disturbance. This estimate is then used to compensate for the disturbance effects. No additional sensors are required, which is particularly relevant in products such as Disk drives where cost is a major concern. The effectiveness of the disturbance observer in rejecting shock and vibration disturbances is demonstrated in simulation and shake table experiments. The vibration experiments showed a decrease in the position error of 61%-96% at frequencies below 100 Hz. The maximum position error due to an experimental shock disturbance was decreased by 59%. The effects of noise in the position error signal are also discussed.
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increased disturbance rejection in Magnetic Disk drives by acceleration feedforward control and parameter adaptation
Control Engineering Practice, 1997Co-Authors: M T White, Masayoshi TomizukaAbstract:Abstract As the density of data on Magnetic Disk drives increases, so does the need for more precise position control of the read/write head, especially in the presence of internal and external disturbances. This is achieved by measuring the acceleration of the drive and feeding the sensor information forward to the actuator. By matching the electromechanical impedance between the disturbance and the position error, the feedforward controller can cancel the effects of the disturbance. Two techniques are presented for designing the feedforward controller. The first method is an infinite impulse response filter that is designed off-line, and the second is a finite impulse response filter that is adapted on-line using the filtered-x LMS algorithm. Both techniques are tested through shake-table experiments, resulting in reductions of the position error signal between 50% and 95%.
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increased disturbance rejection in Magnetic Disk drives by acceleration feedforward control
IFAC Proceedings Volumes, 1996Co-Authors: M T White, Masayoshi TomizukaAbstract:Abstract As the density of data on Magnetic Disk drives increases, so does the need for more precise position control of the read/write head, especially in the presence of internal and external disturbances. This is achieved by sensing the acceleration of the drive and feeding this information forward to the actuator. By matching the electromechanical impedance between the disturbance and the position error, the feedforward controller can cancel the effects of the disturbance. This technique is tested through shake table experiments. Results show a 50% to 90% reduction in the position error signal.
