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Search Publications by: Robert D. McMichael (Assoc)

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Displaying 226 - 250 of 314

Magnetic Anisotropy and Thermal Stability of Ta-pinned Spin Valves

January 1, 2001
Author(s)
R A. Fry, Robert D. McMichael, John E. Bonevich, P J. Chen, William F. Egelhoff Jr., Chang H. Lee
It has recently been found that large uniaxial anisotropy fields in excess of 120 kA/m (1500 Oe) can be created in thin (3 nm to 5 nm) films of Co by obliquely sputtered Ta underlayers. This anisotropy can be used to pin the bottom film of a spin valve

Mathematics and Measurement

January 1, 2001
Author(s)
Ronald F. Boisvert, Michael J. Donahue, Daniel W. Lozier, Robert D. McMichael, Bert W. Rust
In this paper we describe the role that mathematics plays in measurement science at NIST. We first survey the history behind NIST's current work in this area, starting with the NBS Math Tables project of the 1930s. We then provide examples of more recent

Surface and interface effects in the growth of giant magnetoresistance spin valves for ultrahigh-density data-storage applications

January 1, 2001
Author(s)
William F. Egelhoff Jr., P J. Chen, Cedric J. Powell, Robert McMichael, Mark D. Stiles
The current generation of hard disk drives use Giant Magnetoresistance (GMR) spin valves as the read-head because the GMR effect is currently the most sensitive way to detect magnetic fields at submicron length scales and data rates of approximately equal}

Strong Anisotropy in Thin Magnetic Films Deposited on Obliquely Sputtered Ta Underlayers

November 1, 2000
Author(s)
Robert McMichael, C G. Lee, John E. Bonevich, P J. Chen, W. Wyatt Miller, William F. Egelhoff Jr.
Anisotropy fields in excess of 120 kA/m (1500 Oe) have been produced in 3-5 nm- thick polycrystalline films of Co by oblique sputtering of Ta underlayers. The unusually high anisotropy is magnetostatic in origin, and is induced by corrugations on the

Micromechanical Detectors for Ferromagnetic Resonance Spectroscopy

September 1, 2000
Author(s)
John M. Moreland, Pavel Kabos, Albrecht Jander, M. Loehndorf, Robert McMichael, C G. Lee
We demonstrate micromechanical detection of ferromagnetic resonance (FMR) in thin magnetic films. FMR spectroscopy is performed on nanometer scale samples integrated with a micromachined silicon cantilever. We present several techniques by which the FMR

Ferromagnetic Resonance Spectroscopy with a Micromechanical Calorimeter Sensor

August 1, 2000
Author(s)
John M. Moreland, M. Loehndorf, Pavel Kabos, Robert McMichael
We describe a new type of ferromagnetic resonance (FMR) spectroscopy that is based on a calorimeter sensor. We use an atomic force microscopy cantilever coated with a ferromagnetic thin film as a bimaterial sensor to measure absorption of microwaves at 9

Absolute Magnetic Moment Measurements of Nickel Spheres

May 1, 2000
Author(s)
Robert D. Shull, Robert D. McMichael, L Swartzendruber, Stefan D. Leigh
The preparation and measurement of nickel spheres for use in the calibration of magnetometers are described. The absolute value of the magnetic moment of a set these spheres near room temperature was measured using the Faraday method. The variations of

Behavior of MAG Standard Problem No. 2 in the Small Particle Limit

May 1, 2000
Author(s)
Michael J. Donahue, Donald G. Porter, Robert D. McMichael, J Eicke
For a uniformly magnetized rectangular particle with dimensions in the ratio 5 : 1 : 0.1, the coercive and switching fields in the (1,1,1) direction are determined to be H c / M s = 0.057069478 and H s / M s = 0.057142805. Previous micromagnetic

Domain Wall Traps for Low-Field Switching of Submicron Elements

May 1, 2000
Author(s)
Robert D. McMichael, J G. Eicke, Michael J. Donahue, Donald G. Porter
In magnetic random access memory, power consumption depends on the coercivity of the magnetic elements in the memory cells. In this article a new method is described that uses a domain wall trap element shape to reduce both the coercivity and the

Exchange Bias Relaxation in CoO-Biased Films

May 1, 2000
Author(s)
Robert McMichael, Chang H. Lee, Mark D. Stiles, F Serpa, P J. Chen, William F. Egelhoff Jr.
Because the memory of the bias direction is carried by the antiferromagnetic order in exchange bias films, the stability of the antiferromagnetic order is critical to the existence of the exchange bias field. Ferromagnetic resonance was used to measure the

Switching Mechanism of Single Domain Particles in a Two-Dimensional Array

September 1, 1999
Author(s)
Martha Pardavi-Horvath, G Vertesy, B Keszei, Z Vertesy, Robert D. McMichael
The mechanism of switching of uniaxial, single domain, single crystalline epitaxial garnet particles on a 2D square array was investigated. The anisotropy field of the sample is 2 kOe, while the gaussian switching field distribution is 280 85 Oe. The