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Search Publications by: Hans Nembach (Assoc)

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Displaying 26 - 50 of 66

Observation of spin-orbit effects with spin rotation symmetry

October 13, 2017
Author(s)
Alisha Humphries, Tao Wang, Eric R. Edwards, Shane Allen, Justin Shaw, Hans Nembach, John Xiao, Thomas J. Silva
The spin-orbit interaction in a nonmagnetic/magnetic multilayer has been intensively studied due to its efficient conversion between a spin current and a charge current. In the spin Hall/Rashba-Edelstein effects (SHE/REE) and inverse spin Hall/Rashba

Stoner vs. Heisenberg: Ultrafast exchange reduction and magnon generation during laser-induced demagnetization

December 28, 2016
Author(s)
Thomas J. Silva, Hans T. Nembach, Justin M. Shaw, Emrah Turgut, Dmitriy Zusin, Dominik Legut, Karel Carva, Ronny Knut, Cong Chen, Zhensheng Tao, Stefan Mathias, Martin Aeschlimann, Peter Oppeneer, Henry Kapteyn, Margaret Murnane, Patrik Grychtol
Understanding how the electronic band structure of a ferromagnetic material is modified during laser-induced demagnetization on femtosecond timescales has been a long-standing question in condensed matter physics. Here, we use ultrafast high harmonics to

Anomalously low magnetic damping of a metallic ferromagnet

May 16, 2016
Author(s)
Justin M. Shaw, Martin Schoen, Danny Thonig, Michael L. Schneider, Thomas J. Silva, Hans T. Nembach, Olle Eriksson, Olof Karis
The phenomenology of magnetic damping is of critical importance to devices which seek to exploit the electronic spin degree of freedom since damping strongly affects the energy required and speed at which a device can operate. However, theory has struggled

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

Generation of bright phase-matched circularly-polarized extreme ultraviolet high harmonics

December 8, 2014
Author(s)
Justin M. Shaw, Patrik Grychtol, Dmitriy Zusin, Ronny J. Knut, Tenio Popmintchev, Hans T. Nembach, Avner Fleischer, Henry Kapteyn, Margaret Murnane, Ofer Kfir, Oren Cohen
Circularly-polarized extreme UV and X-ray radiation provides valuable access to the structural, electronic and magnetic properties of materials. To date, this capability was available only at large-scale X-ray free-electron lasers or synchrotrons. Here we

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