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A new type of dual spin valve (DSV) structure with enhanced giant magnetoresistance (GMR) ratio is proposed, and the performance is characterized by the prototype read heads. The bottom part of DSV is kept as a synthetic pinned structure and only the top part adopts a monolayer pinned structure. The top monolayer pin DSV (TM-DSV) showed three percentage points higher GMR ratio and 20% higher [DELTA]R value. After the mechanical lapping process, the monolayer pinned layer can be stabilized by not only sense current but also large stress induced anisotropy due to Villari effect. After the quantitative analysis, the induced stress is measured to be about 4.2 x [10.sup.9] N/[m.sup.2]. The bias point was tuned by adjustment of Cu spacer layer thickness using the RKKY interaction between pinned layer and free layer. There is no reliability concern related to the monolayer pinned structure. In a perpendicular magnetic recording system, TM-DSV technology could successfully demonstrate the output of 35.5 mV/[micro]m and ~170 Gbits/[in.sup.2] density feasibility. Index Terms--DSV, monolayer pin, RKKY interaction, stress induced anisotropy, synthetic pin, Villari effect.

Newly designed coplanar cross wire layout for magnetic cellular automata (MCA) and fabrication of two different systems are presented. The capability of the complex system to reach an energy minimum combined with the demonstration of all combinations of the smaller system indicated the physical feasibility and reliability of a cross wire system in MCA.

The different magnetization reversal mechanisms depending on the vortex wall helicities instead of the uniformity of the ring linewidth are described. The simulations have shown that the actual magnetization reversal process is determined by the helicities of the vortex domain walls at the two ends of the onion state.

A theory is developed in the presence of a longitudinal applied field for the localized surface magnetic polaritons in hollow magnetic cylinders or tubes. The results have shown that as the outer radius is increased, the surface polariton branches near the light line have reduced in frequency and the localization properties are modified because of strong retardation effects.

The dynamics of vortices driven by spin-momentum transfer in magnetic tunnel junction nanopillars containing a vortex in the hard ferromagnetic pinner layer (PL) and a vortex in the soft ferromagnetic free layer (FL) are examined. The results have shown that PL vortex handedness should be controlled for optimal device operation.

The performance of cooling fans is enhanced by designing a novel brushless dc motor with a three dimensional stator structure by using soft magnetic composite to reduce the hub size and allow more airflow. The design with the soft magnetic composite (SMC) has reduced the hub size of a fan when compared to conventional fan motors and has consequently resulted in an increase of airflow.

The experimental results of soft x-ray resonant magnetic scattering from a pattern of microscopic Permalloy rings are described. The measurements of the scattering from the stable magnetic configurations such as vortex and onion commonly seen for the ring structures and the variations in the diffraction profile are discussed.

Magnetic transmission x-ray microscopy (M-TXM) is used for imaging domain walls in magnetic ring structures formed [Ni.sub.81][Fe.sub.19] nanowires. Domain walls are observed by comparing images obtained from opposite field sequences or else domain wall propagation observed by comparing successive images in a particular field sequence.

The magnetization reversal process in rectangular and elliptical ferromagnetic ring structures is studied by using various contact configurations. Magnetoresistance measurements in combination with micromagnetic simulations are used for understanding the magnetization reversal mechanism in both the ring geometries.

The separation of two types of magnetic particles is investigated along with the study of motion of particles. Based on the theory of magnetophoresis, the two types of magnetic particles are separated with different magnetophoretic mobilities using an electrically controlled microdevice.

The current-driven magnetization reversal of exchange-biased spin-valve giant magnetoresistive nanopillars with a magnetically pinned ferromagnetic layer is investigated. Current-driven magnetzation reversal of a ferromagnetic layer is found to take place even when the layer is pinned by the exchange bias induced by an antiferromagnet.