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Search Publications by: Matthew Pufall ()

Displaying 51 - 60 of 60

Current-Driven Microwave Dynamics in Magnetic Point Contacts as a Function of Applied Field Angle

December 1, 2004

Author(s)

William Rippard, Matthew Pufall, Shehzaad F. Kaka, Thomas J. Silva, Stephen E. Russek

We have measured microwave frequency, current-driven magnetization dynamics in point contacts made to Co 90Fe 10/Cu/Ni 80Fe 20 spin valves as a function of applied field strength and angle relative to the film plane. As the field direction is varied from

Spin transfer switching of spin valve nanopillars using nanosecond pulsed currents

October 29, 2004

Author(s)

Shehzaad F. Kaka, Matthew Pufall, William Rippard, Thomas J. Silva, Stephen E. Russek, Jordan A. Katine, Matt Carey

Spin valve nanopillars are reversed via the mechanism of spin momentum transfer using current pulses applied perpendicular to the film plane of the device. The applied pulses were varied in amplitude from 1.8 to 7.8 mA, and varied in duration within the

Large-angle, gigahertz-rate random telegraph switching induced by spin-momentum transfer

July 27, 2004

Author(s)

Matthew Pufall, William Rippard, Shehzaad F. Kaka, Stephen E. Russek, Thomas J. Silva, Jordan A. Katine, Matt Carey

We show that a spin-polarized dc current passing through a small magnetic element induces two-state, random telegraph switching of the magnetization via the spin-momentum transfer effect. The resistances of the states differ by up to 50% of the change due

Direct-Current Induced Dynamics in Co 90 Fe 10 /Ni 80 Fe 20 Point Contacts

January 16, 2004

Author(s)

William Rippard, Matthew Pufall, Shehzaad F. Kaka, Stephen E. Russek, Thomas J. Silva

We have directly measured coherent high-frequency magnetization dynamics in ferromagnetic films induced by a spin-polarized dc current. The precision frequency can be tuned over a range of several gigahertz by varying the applied current. The frequencies

Materials dependence of the spin-momentum transfer efficiency and critical current in ferromagnetic metal/Cu multilayers

July 14, 2003

Author(s)

Matthew Pufall, William Rippard, Thomas J. Silva

We have quantitatively compared spin momentum transfer effects in FM/Cu multilayers, with FM = Co, Co 90Fe 10, Ni 80Fe 20, Ni 40Fe 10Cu 50, and Fe. All of the measured multilayers exhibited an abrupt step in the resistance at a critical current I c, the

Nonlinear magnetooptic measurement of flux propagation dynamics in thin Permalloy films

March 12, 2003

Author(s)

Thomas J. Silva, Matthew Pufall, Pavel Kabos

Time-resolved nonlinear optics are used to study the propagation of magnetic flux pulses in a 250 nm Permalloy film. The flux is generated in the film by coupling it to a coplanar waveguide structure driven with broadband voltage pulses. Flux pulses

Quantitative Studies of Spin-Momentum-Transfer-Induced Excitations in Co/Cu Multilayer Films Using Point-Contact Spectroscopy

February 24, 2003

Author(s)

William Rippard, Matthew Pufall, Thomas J. Silva

We have measured current-induced magnetic excitations in a variety of exchange-coupled Co/Cu multilayers using point-contact spectroscopy. A step in the DC resistance and corresponding peak in dV/dI are observed at a critical current Ic whose value

Detection of coherent and incoherent spin dynamics during the magnetic switching process using vector-resolved nonlinear magneto-optics

September 16, 2002

Author(s)

Thomas J. Silva, Pavel Kabos, Matthew Pufall

It is usually assumed that magnetic switching proceeds via coherent rotation under conditions of high symmetry. There is no a priori reason to expect an inhomogeneous response when a uniform magnetic torque is applied to a homogeneous ferromagnet. We test

Simultaneous measurement of surface and bulk vector magnetization dynamics in thin Ni-Fe films

February 1, 2002

Author(s)

Matthew Pufall, Thomas J. Silva

The dynamics of the surface and 'bulk' magnetization vectors of a Ni-Fe thin film were measured using the time-resolved second harmonic and linear magnetooptical Kerr effects. Films of 50, 250, and 400 nm thickness were measured. The magnetization dynamics

Design and performance of an inductive current probe for integration into the trace suspension assembly

January 1, 2002

Author(s)

Anthony B. Kos, Thomas J. Silva, Pavel Kabos, Matthew Pufall, Donald C. DeGroot, L Webb, M Even

A low-cost, inductive current probe designed for integration into a disk drive trace suspension assembly is described. The main consideration for this design was to use the same materials currently found in trace suspension assemblies, and thus reducing