Seagate Technologies

Bloomington, MN, United States

Seagate Technologies

Bloomington, MN, United States
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Sharma A.,University of Minnesota | Zhu Y.,University of Minnesota | Reddy M.,University of Minnesota | Hubel A.,University of Minnesota | And 3 more authors.
Springer Proceedings in Physics | Year: 2014

This paper reviews the synthesis of magnetic multilayerd nanowires that have a wide range of applications. Specifically of interest in this review are the applications of magnetic manipulation and separation of cells, which are important for potential cancer therapies. Compared to other magnetic nanoparticles in use today, the nanowires have the advantage of being ferromagnetic and also having high aspect ratios that enable barcoding. These nanobots are synthesized inside nanoporous oxide templates in large batches (1012 per square inch), and they can be composed of any magnetic metal, alloy, or multilayer that can be electroplated. Specific details for the electrochemistry of Galfenol deposition are given. Galfenol is an exciting new magnetostrictive material with durable mechanical properties. Next, a protocol is described for full removal of the growth contact prior to release of the nanobots from their oxide template. This mitigates aggregation which inhibits cellular uptake. Feasibility of manipulation and separation was shown using canine bone cancer (os-teosarcoma) cells which internalized the nanobots, enabling magnetic cellular control. In addition, initial toxicity studies indicate that the nanobots are not cytotoxic. These studies merely scratch the surface of the potential use of nanobots for diagnosis and therapy in the near future. © Springer International Publishing Switzerland 2014.


Jalli J.,University of Alabama | Hong Y.-K.,University of Alabama | Bae S.,University of Alabama | Lee J.-J.,University of Alabama | And 8 more authors.
Journal of Applied Physics | Year: 2011

Single crystals of Zr-substituted Zn-Y (Zr-ZnY; Ba2Zn 2ZrxFe12-xO22) were grown from the flux system of BaCO3 and B2O3 by a high temperature slow cooling flux method. X-ray diffraction pattern confirmed the crystal structure with Zn-Y composition. The single crystals were characterized for magnetic and microwave properties. The measured anisotropy field (HA) and the in-plane magnetization (σs) are 13 kOe and 52.0 emu/g, respectively. Ferrimagnetic resonance measurements show 18 Oe of linewidth (δH) at 9 GHz. The combination of low δH with a high δHA in Zr-ZnY hexaferrite is suitable for microwave devices, which can operate with low external biasing field. © 2011 American Institute of Physics.


Abo G.S.,University of Alabama | Hong Y.-K.,University of Alabama | Choi B.-C.,University of Victoria | Donahue M.J.,U.S. National Institute of Standards and Technology | And 6 more authors.
IEEE Transactions on Magnetics | Year: 2012

The scaling effect of permalloy s-shaped element, a rectangular element with appendages, on operating fields, H x and H y, was investigated by micromagnetic computer simulations for and or or logic. The optimized combination of operating fields (H x, H y) was found to be (27.7 ± 9.9, -16.7 ± 8.8), (37.9 ± 12.4, -25.9 ± 6.0), and (42.2 ± 8.8, -23.9 ± 4.0) in kA/m for the 100, 50, and 30 nm long s-shaped elements, respectively. As the s-shaped element is scaled down, the allowable deviation from the optimized operating fields becomes smaller and optimized operating fields shift to higher field. © 2012 IEEE.


Lentmaier M.,TU Dresden | Sridharan A.,Seagate Technologies | Costello Jr. D.J.,University of Notre Dame | Zigangirov K.S.,University of Notre Dame | And 2 more authors.
IEEE Transactions on Information Theory | Year: 2010

An iterative decoding threshold analysis for terminated regular LDPC convolutional (LDPCC) codes is presented. Using density evolution techniques, the convergence behavior of an iterative belief propagation decoder is analyzed for the binary erasure channel and the AWGN channel with binary inputs. It is shown that for a terminated LDPCC code ensemble, the thresholds are better than for corresponding regular and irregular LDPC block codes. © 2010 IEEE.


SAN DIEGO--(BUSINESS WIRE)--Illumina, Inc. (NASDAQ: ILMN) announced today that John W. Thompson will join the company’s Board of Directors on May 3, 2017, bringing extensive technology leadership experience to the company. Mr. Thompson’s executive leadership experience includes having served in chief executive officer roles at Symantec and Virtual Instruments, as well as 28 years of prior leadership experience at IBM where he held senior roles in sales, marketing, software development, and as general manager of IBM Americas. He is chairman of the board at Microsoft and has served on the corporate boards of Symantec, NIPSCO (Northern Indiana Public Service Company), Fortune Brands, Seagate Technologies, and United Parcel Service (UPS). Mr. Thompson is a member of the board of trustees for the Wetlands America Trust and formerly a member of the national board of Teach for America. In addition, he has served on several government commissions including the Financial Crisis Inquiry Commission, the National Infrastructure Advisory Council, and the Silicon Valley Blue Ribbon Task Force on Aviation Security and Technology. “John brings a great breadth of knowledge and experience in the public and private sectors having served in such a wide range of leadership and advisory roles,” said Francis deSouza, Illumina President and Chief Executive Officer. “His wealth of technology expertise will help us continue to grow and scale our business in the years to come.” Mr. Thompson received his B.A. in business administration from Florida A&M University and his M.S. in management science from MIT’s Sloan School of Management. Illumina is improving human health by unlocking the power of the genome. Our focus on innovation has established us as the global leader in DNA sequencing and array-based technologies, serving customers in the research, clinical, and applied markets. Our products are used for applications in the life sciences, oncology, reproductive health, agriculture, and other emerging segments. To learn more, visit www.illumina.com and follow @illumina.


Bhat V.,University of Kentucky | Woods J.,University of Kentucky | Hastings J.T.,University of Kentucky | De Long L.E.,University of Kentucky | And 5 more authors.
Proceedings - 2011 International Conference on Electromagnetics in Advanced Applications, ICEAA'11 | Year: 2011

We have performed broad-band (10 MHz-20 GHz) and tuned cavity (9.7 GHz) ferromagnetic resonance measurements on permalloy thin films patterned with square lattices of circular, square and diamond-shaped antidots of various sizes and separations. We observe remarkably reproducible mode structures in the low-frequency, hysteretic regime in which various domain wall patterns and unsaturated magnetization textures exist and are strongly affected by the geometry of the antidot lattice. The field, frequency and angular dependences of the observed modes (some of which have not been previously observed) are generally in good agreement with our micromagnetic simulations. © 2011 IEEE.


Bhat V.,University of Kentucky | Woods J.,University of Kentucky | De Long L.E.,University of Kentucky | Hastings J.T.,University of Kentucky | And 5 more authors.
Physica C: Superconductivity and its Applications | Year: 2012

Previous ferromagnetic resonance (FMR) studies of ferromagnetic (FM) thin films patterned with antidot (AD) arrays have generally avoided the low-field, hysteretic regime that is dominated by irreversible domain wall (DW) dynamics in unpatterned films. Moreover, FM vortices have not yet been identified and systematically studied in films patterned with AD lattices (ADLs). We have studied DC magnetization and broad-band FMR data for permalloy thin films of thickness t ≈ 25 nm, patterned with square lattices of square-shaped AD of width D and separation d = 1000 nm. We observe highly reproducible magnetic hysteresis curves and FMR spectra in the low-field reversal regime (i.e., applied magnetic fields H < H C, where H C is the coercive field), which indicates the ADL enforces a reproducible evolution of spin textures compared to the more random behavior of DW evolution in unpatterned films. The width of the reversal regime (2H C) and the field separation between observed FMR modes increases with D for a fixed separation d. Our micromagnetic simulations suggest these effects are consequences of both edge pinning of moments by individual AD, or DW pinning by the extended ADL, which involves two distinct length scales L ≈ d and L ≫ d, respectively. FM vortices are observed in our simulations, and their stability sensitively depends upon the AD size and applied magnetic field history. © 2012 Elsevier B.V. All rights reserved.


Zhang Z.,CA Technologies | Liu K.,CA Technologies | Jin E.X.,CA Technologies | Dovek M.M.,CA Technologies | And 5 more authors.
IEEE Transactions on Magnetics | Year: 2016

Heat-assisted magnetic recording (HAMR) has become one of the leading approaches to increase the areal density in hard disk drives to several Tb/in2. Laser-induced protrusion significantly impacts the HAMR heads' performance and lifetime. Nonetheless, the pointy local protrusion amount is hard to accurately quantify by touchdown sensors. Based on the previous indirect thermal-mechanical studies with different sensors and techniques, a new methodology is developed to measure the laser-induced protrusion by burnishing the head during writing with laser powered ON and by utilizing atomic force microscopy scans. This burnish method requires the air-bearing surface (ABS) to physically contact the rotating disk without an excessive overdrive, which relies on the precise settings of the touchdown sensors and the detection methods. The time dependence of the burnish behavior is studied. The results show that its time constant is much longer than the pure thermal and mechanical time constants. The repeatability of the experiment is validated. The local protrusion induced by the laser is in the range of 2-5 nm based on current head design. Accordingly, the detailed studies about heater power effects and protrusion amount as a function of laser power have been conducted. In addition, the impact of varying degrees of stiffness of the ABS is discussed. © 1965-2012 IEEE.


Chen Y.,Seagate Technologies | Song D.,Seagate Technologies | Qiu J.,Seagate Technologies | Kolbo P.,Seagate Technologies | And 8 more authors.
IEEE Transactions on Magnetics | Year: 2010

We review the 2 Tbit/in2 reader design landscape based on existing knowledge and projection.We found that the reader signal-to-noise ratio (SNR) requirement will be highly challenging due to the rapid increase in noise and the additional requirements from assisted writing. An acceptable level of channel bit density can be achieved in spite of a slow head-to-media spacing (HMS) reduction provided that both the shield-to-shield (SS) spacing and the "a" parameter scale with the bit length. We expect the side reading control for high ktpi to be difficult, and potentially a reader side shield will be required. The reader will likely use a higher quality MgO tunneling giant magnetoresistance (TGMR) stack with improved permanent-magnet coercivity. Certain new structures such as the differential reader or the trilayer will likely be part of the solution. © 2010 IEEE.

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