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Search Publications by: Thomas J. Silva (Fed)

Displaying 201 - 225 of 270

Different Dynamic and Static Magnetic Anisotropy in Thin Permalloy Films

July 6, 2003

Author(s)

Radek Lopusnik, John P. Nibarger, Thomas J. Silva, Zbigniew J. Celinski

The values of uniaxial anisotropy Hk in thin polycrystalline Permalloy films measured by static and dynamic methods differ by as much as a factor 1.5. The anisotropy obtained with a pulsed inductive microwave magnetometer in 2.5-100 nm thick Permalloy

Cyrogenic pulsed inductive microwave magnetometer

May 15, 2003

Author(s)

Anthony B. Kos, John P. Nibarger, Radek Lopusnik, Thomas J. Silva, Zbigniew J. Celinski

A cryogenic pulsed inductive microwave magnetometer is used to characterize the switching dynamics in thin-film materials at low temperatures and microwave frequencies. The system is contained inside a 20-cm-dia ultrahigh vacuum chamber and cooled by a

Damping as a function of pulsed field amplitude and bias field in thin film Permalloy

March 31, 2003

Author(s)

John P. Nibarger, Radek Lopusnik, Thomas J. Silva

We have measured the step response in thin film Permalloy as a function of both a hard-axis pulsed field amplitude and easy-axis longitudinal magnetic bias field using a pulsed inductive microwave magnetometer. The bias field ranged from 0 to 8000 A/m (0

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

Pulsed inductive microwave magnetometer

October 1, 2002

Author(s)

Anthony B. Kos, Thomas J. Silva, Pavel Kabos

We describe the apparatus, software, and measurement procedures for a pulsed inductive microwave magnetometer (PIMM). PIMM can measure the dynamical properties of materials used in recording heads for magnetic storage applications and it can be used as a

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

High-Frequency Behavior and Damping of Fe Co N-Based High-Saturation Soft Magnetic Films

January 1, 2002

Author(s)

Thomas J. Silva, S X. Wang, Sun X. N., Anthony B. Kos

Magnetization dynamics measurements at subnanosecond time scale have been performed on Fe Co N high-saturation soft magnetic films with Permalloy nanolayer seeds and having a saturation magnetization of 1.9 MA/m (1900 emu/cm3). The damping parameter a

Measurement of Dynamic Properties in Thin-Films

December 1, 2001

Author(s)

Thomas J. Silva

I present a summary of the various techniques available for the determination of response times in magnetic recording head materials. In addition, I derive useful equations for the interpretation of data in the context of the Landau-Lifshitz-Gilbert

High Frequency Measurements of CoFeHfO Thin Films

July 1, 2001

Author(s)

Stephen E. Russek, Pavel Kabos, Thomas J. Silva, Fred B. Mancoff, D Wang, Z. T. Qian, J. M. Daughton

High frequency measurements of the transverse susceptibility and damping constant of CoFeHfo thin films have been made over a frequency range of 0.1 GHz to 6 GHz as a function of film resistivity, thickness, and temperature. The films show relatively low

Determination of Average Demagnetizing Fields in Longitudinal Magnetic Recording Using Nanosecond Field Pulses

September 4, 2000

Author(s)

A Moser, D Weller, N D. Rizzo, Thomas J. Silva

The demagnetizing field across bit transitions in longitudinal recording media is measuredquantitatively as a function of linear density using a quasi static write/read tester. Bit transitions with varying linear densities in the range 500-6000 flux