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Search Publications by: Thomas J. Silva (Fed)

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Displaying 26 - 50 of 135

Suppression of Spin Pumping between Ni80Fe20 and Cu by a Graphene Interlayer

June 7, 2015
Author(s)
William J. Gannett, Mark W. Keller, Hans Nembach, Thomas J. Silva, Ann Chiaramonti Debay
Abstract We compare ferromagnetic resonance measurements of Py (Ni80Fe20) films sputtered onto Cu(111) with and without a graphene (Gr) interlayer grown by chemical vapor deposition before Py deposition. We find the expected damping enhancement from spin

Higher order perpendicular magnetic anisotropy in ultra-thin Co60Fe20B20 layers and the observation of an easy cone state.

June 1, 2015
Author(s)
Justin M. Shaw, Hans T. Nembach, Mathias A. Weiler, Martin A. Schoen, Thomas J. Silva, Jonathan Z. Sun, Daniel C. Worledge
We used broadband ferromagnetic resonance (FMR) spectroscopy to measure the second and forth order perpendicular magnetic anisotropies in Ta/ Co60Fe20B20/MgO layers over a thickness range of 0.8-5 nm. For a thickness greater than 1.0 nm, the easy axis is

Terbium-Doped Magnetite Nanocrystals for Multimodal Imaging Agents

May 1, 2015
Author(s)
Katherine P. Rice, Stephen E. Russek, Roy H. Geiss, Justin M. Shaw, Robert J. Usselman, Eric R. Evarts, Thomas J. Silva, Hans T. Nembach, Elke Arenholz, Yves Idzerda
High quality cubic Tb-doped magnetite nanocrystals have been fabricated and have shown that the Tb is incorporated into the octahedral 3+ sites. Magnetization and FMR data indicate that the Tb spins are weakly coupled to the iron spin lattice at room

Temperature-dependent structure of Tb-doped magnetite nanoparticles

February 13, 2015
Author(s)
Katherine P. Rice, Stephen E. Russek, Roy H. Geiss, Justin Shaw, Robert J. Usselman, Eric R. Evarts, Thomas J. Silva, Hans Nembach, Elke Arenholz, Yves U. Idzerda
High quality 5 nm cubic Tb-doped magnetite nanoparticles have been synthesized by a modified wet-chemical method to investigate tailoring of magnetic properties for imaging and biomedical applications. We show that the Tb is incorporated into the

Phase-Sensitive Detection of Spin Pumping via the ac Inverse Spin Hall Effect

October 6, 2014
Author(s)
Thomas J. Silva, Justin M. Shaw, Hans T. Nembach, Mathias A. Weiler
Sources of pure spin currents are a fundamental building block of spintronic devices. In ferromagnet/normal metal heterostructures, spin currents are generated at ferromagnetic resonance. This is known as spin pumping, where spin currents of both dc and ac

Head and Media Challenges for 3 Tb/in 2 Microwave Assisted Magnetic Recording

February 3, 2014
Author(s)
Thomas J. Silva, Justin M. Shaw, Hans T. Nembach, Mike Mallary, Kumar Srinivasan, Gerado Bertero, Dan Wolf, Christian Kaiser, Michael Chaplin, Mahendra Pakala, Leng Qunwen, Yiming Wang, Carl Elliot, Lui Francis
A specific design for Microwave Assisted Magnetic Recording (MAMR) at about 3Tb/in 2 (0.47 Tb/cm 2 or 4.7 Pb/m 2) is discussed in detail to highlight the challenges of MAMR and to contrast its requirements with conventional Perpendicular Magnetic Recording

Reply to "Comment on: 'Ultrafast Demagnetization Measurements Using Extreme Ultraviolet Light: Comparison of Electronic and Magnetic Contributions'"

September 4, 2013
Author(s)
Justin Shaw, Thomas J. Silva, Hans Nembach, Emrah Turgut, Patrik Grychtol, Chan La-O-Vorakiat, Henry C. Kapteyn, Margaret M. Murnane, Stefan Mathias, Martin Aeschlimann, Claus Schneider, Daniel E. Adams
In the following, we show that the conclusions of our article titled "Ultrafast Demagnetization Measurements Using Extreme Ultraviolet Light: Comparison of Electronic and Magnetic Contributions" are correct. The Comment of Vodungbo et al. argues that a

Controlling the Competition between Optically Induced Ultrafast Spin-Flip Scattering and Spin Transport in Magnetic Multilayers

May 7, 2013
Author(s)
Justin Shaw, Hans Nembach, Thomas J. Silva, Margaret M. Murnane, Henry C. Kapteyn, Martin Aeschlimann, Claus M. Schneider, Emrah Turgut, Stefan Mathias, Patrik Grychtol, Chan La-O-Vorakiat, Dennis Rudolf, Roman Adam
The study of ultrafast dynamics in magnetic materials provides rich opportunities for greater fundamental understanding of correlated phenomena in solid-state matter, because many of the basic microscopic mechanisms involved are as-yet unclear and are

Ultrafast element-specific magnetization Dynamics of complex magnetic materials on a table-top

December 21, 2012
Author(s)
Thomas J. Silva, Justin M. Shaw, Hans T. Nembach, Chan La-O-Vorakiat, Henry C. Kapteyn, Margaret M. Murnane, Stefan Mathias, Roman Adam, Patrik Grychtol, Martin Aeschlimann, Claus M. Schneider, Emrah Turgut, Dennis Rudolf
We review recent progress in femtosecond magnetization dynamics probed by extreme ultraviolet pulses from high-harmonic generation. In a transverse magneto-optical Kerr geometry, we establish an ultrafast, element-specific experimental capability - on a

Spin Dynamics in the Time and Frequency Domain

September 15, 2012
Author(s)
Thomas J. Silva
The current status of experimental approaches to analyze the spin wave dynamics in ferromagnetic nanoscale structures is reviewed. Recent developments in frequency- and field swept spectroscopy to determine the resonant response of nanoscale ferromagnets

Ultrafast manetization enhancement in metallic multilayers driven by superdiffusive spin current

September 4, 2012
Author(s)
Thomas J. Silva, Justin M. Shaw, Hans T. Nembach, Dennis Rudolf, Chan La-O-Vorakiat, Marco Battiato, Roman Adam, Emrah Turgut, Stefan Mathias, Margaret M. Murnane, Henry C. Kapteyn, Claus M. Schneider
Uncovering the physical mechanisms that govern ultrafast charge and spin dynamics is crucial for understanding correlated matter as well as the fundamental limits of ultrafast spin-based electronics. Spin dynamics in magnetic materials can be driven by

Propagation and control of nano-scale, magnetic droplet solitons

June 11, 2012
Author(s)
Thomas J. Silva, Mark Hoefer, Matteo Sommacal
The propagation and controlled manipulation of strongly nonlinear, two-dimensional solitonic states in a thin, anisotropic ferromagnet is theoretically demonstrated. It has been recently proposed that spin polarized currents in a nanocontact device could

Probing the timescale of the exchange interaction in a ferromagnetic alloy

January 27, 2012
Author(s)
Justin M. Shaw, Stefan Mathias, Chan La-O-Vorakiat, Hans T. Nembach, Thomas J. Silva, Mark Siemens, Henry Kapteyn, Margaret Murnane
The underlying physics of all ferromagnetic behavior is the cooperative interaction between individual atomic magnetic moments that results in a macroscopic magnetization. In this work, we use extreme ultraviolet pulses from high-harmonic generation as an