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Thomas J. Silva, Justin M. Shaw, Hans T. Nembach, Mathias Weiler, Martin Schoen
The damping α of the spinwave resonances in 75 nm, 120 nm, and 200 nm -thick Permalloy films is measured via vector-network- analyzer ferromagnetic-resonance (VNA-FMR). Inductive coupling between the sample and the waveguide leads to an additional
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
Stephen E. Russek, Eric R. Evarts, Robert J. Usselman
Nanoscale magnetic devices and particles are being developed for a wide variety of applications including magnetic memory, nanoscale sensors, magnetic resonance imaging (MRI) agents, and therapeutic agents. Magnetic nanoparticles are also endogenous to the
Hyuk-Jae Jang, Jun-Sik Lee, Sujitra J. Pookpanratana, Ich C. Tran, Curt A. Richter, Christina A. Hacker
We present the results of experiments that explore the influence of molecular self-assembled monolayers (SAMs) on characteristics of spin injection into an organic semiconductor, Alq3 [tris-(8-hydroxyquinoline) aluminum] from a ferromagnetic metal, Co. Two
Burm Baek, William H. Rippard, Matthew R. Pufall, Samuel P. Benz, Stephen E. Russek, Horst Rogalla, Paul D. Dresselhaus
Traditionally, superconductivity and magnetism have had a mutually exclusive relationship. However, the physics of superconductor-ferromagnet hybrid structures turned out to be far from being simply destructive, which has led to the hope of a new breed of
Larysa Tryputen, Feng Guo, Liu Frank, T. N. Anh Nguyen, Majid Mohseni, Sunjae Chung, Yeyu Fang, Johan Akerman, Robert McMichael, Caroline Ross
The magnetization behavior, magnetic anisotropy and domain congurations of Co/Pd multilayers with perpendicular magnetic anisotropy capped with permalloy is investigated using magnetometry, magnetic force microscopy and ferromagnetic resonance. The
Burm Baek, William H. Rippard, Matthew R. Pufall, Samuel P. Benz, Stephen E. Russek, Horst Rogalla, Paul D. Dresselhaus
Combining superconducting and magnetic materials to create novel superconducting devices has been motivated by the discovery of the Josephson critical current (Ics) oscillations with magnetic layer thickness and the demonstration of devices with switchable
We examine the Dyakonov and Perel theory of the Spin Hall Effect from the viewpoint of irreversible thermodynamics. As thermodynamic driving forces we include the effect of the thermal gradient, the gradient of the electrochemical potential (rather than
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
Hyuk-Jae Jang, Sujitra J. Pookpanratana, Alyssa N. Brigeman, Regis J. Kline, James I. Basham, David J. Gundlach, Christina A. Hacker, Oleg A. Kirillov, Oana Jurchescu, Curt A. Richter
Organic semiconductors hold immense promise for the development of a wide range of innovative devices with their excellent electronic and manufacturing characteristics. Of particular interest are non-magnetic organic semiconductors that show unusual
Eric R. Evarts, Ranko R. Heindl, William H. Rippard, Matthew R. Pufall
In a small fraction of magnetic-tunnel-junction-based MRAM devices with in-plane free layers, the write error rates (WERs) are higher than expected on the basis of the macrospin or quasi-uniform magnetization reversal models. In devices with increased WERs
Burm Baek, William H. Rippard, Samuel P. Benz, Stephen E. Russek, Paul D. Dresselhaus
The quantum behavior of Josephson junctions is often exploited to produce superconducting devices with outstanding performance. Josephson junctions can also be used in circuits that perform logic operations in picoseconds and may enable high-performance
Thomas J. Silva, Mathias A. Weiler, Hans T. Nembach, Justin M. Shaw
In a recent Letter, Hahn et al. reported on the detection of an ac voltage in a yttrium iron garnet (YIG)/platinum (Pt) bilayer under the condition of parametrically excited resonance. The authors observe an ac voltage at the frequency of the magnetization
Jacob M. Taylor, Medford Jim, Johannes Beil, Stephen Bartlett, Andrew Doherty, Emmanuel Rashba, David P. DiVincenzo, H Lu, A. C. Gossard
We demonstrate the initialization, full electrical control, and state tomography of an exchange- only spin qubit in a GaAs heterostructure. Decoherence and leakage from the qubit subspace are accounted for with a model of charge noise and fluctuating
We present a modulated microwave approach for quantum computing with qubits comprising three spins in a triple quantum dot. This approach includes single- and two-qubit gates that are protected against low-frequency electrical noise, due to an operating
Jacob M. Taylor, Medford Jim, Johannes Beil, Emmanuel Rashba, H Lu, A. C. Gossard, C. M. Marcus
We introduce a solid-state qubit in which exchange interactions among confined electrons provide both the static longitudinal field and the oscillatory transverse field, allowing rapid and full qubit control via rf gate-voltage pulses. We demonstrate two
Burm Baek, Samuel P. Benz, William H. Rippard, Stephen E. Russek, Paul D. Dresselhaus, Horst Rogalla, Matthew R. Pufall
If Josephson and spintronic technologies can be successfully integrated to produce a cryogenic memory that can be controlled with single-flux quantum pulses, then they may enable ultra-low-power, high-speed computing. We have developed hybrid Josephson
Eric R. Evarts, Matthew R. Pufall, William H. Rippard
We quantitatively compare film-level ferromagnetic resonance (FMR) measurements to device-level FMR measurements on magnetic tunnel junction (MTJ) thin films with in-plane magnetization using both thermal FMR (T-FMR) and field-swept spin torque FMR
We use broadband ferromagnetic resonance spectroscopy and x-ray diffraction to investigate the fundamental origin of perpendicular anisotropy in Co 90Fe 10/Ni multilayers. By careful evaluation of the spectroscopic g-factor, we determine the orbital moment
Stephen E. Russek, Ranko R. Heindl, Thomas Cecil, William H. Rippard
Spin transfer nano-oscillators are small multilayer magnetic devices that undergo microwave oscillations and output a microwave voltage when a bias current is applied. The oscillation frequency is tunable, over a range of 0.5 GHz to 225 GHz, by varying the
Hyuk-Jae Jang, Kurt Pernstich, David J. Gundlach, Oana Jurchescu, Curt A. Richter
We present the observation of magnetoresistance in Co/Ca/Alq3/Ca/NiFe spin-valve devices. Thin Ca layers contacting 150 nm thick Alq3 enable the injection of spin-polarized electrons into Alq3 due to engineering of the band alignment. The devices exhibit
Matthew R. Pufall, William H. Rippard, Stephen E. Russek, Eric R. Evarts
We have measured spin-torque-driven oscillations of Ni80Fe20 free-layer nanocontacts as a function of field direction. For a given field axis angle (10◦ from the surface normal) and magnitude, simply changing the field polarity can significantly alter the
We propose a multilayer structure that allows a reduced switching current with maintaining high thermal stability of the magnetization. It consists of a perpendicular polarizer, a perpendicular free-layer, and an additional free-layer having in-plane
Soo-Man Seo, Kyoung-Whan Kim, Jisu Ryu, Hyun-Woo Lee, Kyung Jin Lee
We study theoretically current-induced dynamics of a transverse magnetic domain wall in bi-layer nanowires consisting of a ferromagnet on top of a nonmagnet having strong spin-orbit coupling. Domain wall dynamics is characterized by two threshold current
Kyoung-Whan Kim, Soo-Man Seo, Jisu Ryu, Kyung Jin Lee, Hyun-Woo Lee
Thin ferromagnetic layers with broken structural inversion symmetry are subject to the Rashba spin-orbit coupling. We examine effects of the Rashba spin-orbit coupling on conduction electron spin dynamics and find that the electric current flowing along