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Search Publications by: Stephen E. Russek (Fed)

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Displaying 101 - 125 of 337

Magnetic Noise in a Low-Power Picotesla Magnetoresistive Sensor

October 25, 2009
Author(s)
Stephen E. Russek, Lu Yuan, Sean Halloran, Fabio C. da Silva, David P. Pappas, John M. Moreland, Sy-hwang Liou, Rui Zhang
We present a design of a low power, compact, magnetoresistive sensor. The key features of the design are(1) decreasing the noise by the use of a 64 element magnetic tunnel junction (MTJ) bridge,(2) reducing the magnetic noise by annealing the MTJ sensors

Temperature dependence of spin-torque-driven self-oscillators

October 15, 2009
Author(s)
William H. Rippard, Matthew R. Pufall, Thomas Cecil, Thomas J. Silva, Stephen E. Russek, M. L. Schneider
We have measured the temperature dependence of spin-torque-driven self-oscillations in point-contact nanooscillators for both in-plane and out-of-plane applied fields. We find that the linewidth for both field geometries is qualitatively similar. In the

Reversal mechanisms in perpendicular magnetic nanostructures

July 16, 2008
Author(s)
Justin M. Shaw, Stephen E. Russek, Michael J. Donahue, Thomas Thomson, Bruce Terris, Michael Schneider, Miles Olsen
We find that the reversal mechanism in magnetic nanostructures is highly dependent on the nature and condition of the edges. Temperature and size dependent reversal properties of fabricated perpendicularly magnetized nanostructures down to 25 nm in

Spin Transfer Precessional Dynamics in Co 60 Fe 20 B 20 Nanocontacts

March 14, 2008
Author(s)
William H. Rippard, Matthew R. Pufall, Michael L. Schneider, Kevin Garello, Stephen E. Russek
We report on the precessional dynamics in spin transfer oscillators having Co 60Fe 20B 20 free layers as a function of annealing time at 225 °C. Repeated annealing reduces the critical current I c by roughly a factor of 3 and increases the tunability of

Dependence of noise in magnetic tunnel junction sensors on annealing field and temperature

March 7, 2008
Author(s)
Stephen E. Russek, David P. Pappas, Sean Halloran, Lu Yuan, Sy-Hwang Liou, Rui Zhang
The minimum detectable field of magnetoresistive sensors is limited by their intrinsic noise. Magnetization fluctuations are one of the crucial noise sources and are related to the magnetization alignment at the antiferromagnetic – ferromagnetic interface

Low-field current-hysteretic oscillations in spin-transfer nanocontacts

April 19, 2007
Author(s)
Matthew Pufall, William Rippard, Michael Schneider, Stephen E. Russek
We have measured spin-transfer-driven, large-amplitude, current-hysteretic, low frequency (less than or equal to} 500 MHz), narrowband oscillations in nanocontacts made to spin valve structures. The oscillations occur in zero field, persist up to 5 mT for

Broadband Electrical Characterization of Multiwalled Carbon Nanotubes and Contacts

March 22, 2007
Author(s)
Paul Rice, T. M. Wallis, Stephen E. Russek, Pavel Kabos
We have welded an individual multiwalled carbon nanotube (MWNT) onto a microlithographically-patterned coplanar waveguide (CPW) and measured the electrical response of the nanotube and the contacts from 100 MHz to 24 GHz. The MWNT was welded to the CPW in

Broadband Electrical Characterization of Multiwalled Carbon Nanotubes and Contacts

March 22, 2007
Author(s)
Thomas M. Wallis, Stephen E. Russek, Pavel Kabos, Paul Rice
The electrical response of an individual multiwalled carbon nanotube (MWNT) and its contacts, welded to a coplanar waveguide (CPW), was measured up to 24 GHz using a technique that removes environment effects. This is the first time MWNT contact effects

Thermal effects on the critical current of spin torque switching in spin valve nanopillars

February 28, 2007
Author(s)
Michael Schneider, Matthew Pufall, William Rippard, Stephen E. Russek, Jordan A. Katine
In spin valve nanopillars, temperature affects the spin torque reversal of the free magnetic layer. The authors compare values of zero temperature critical switching current I c0 extrapolated from room temperature pulsed current switching measurements to