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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.

The gas cluster ion beam technique has been used to smooth the bottom NiFe magnetic shield for magnetic tunnel junction read heads. This approach allows the production an ultrathin tunneling barrier for magnetic tunnel junction read heads.

Magnetic tunnel junctions are fabricated by using radical oxidation to form an AlOx tunneling barrier. The results are discussed in terms of the E-model based on the field-induced distortion of atomic bonds in the oxide barrier.

A study was conducted to analyze the canting of exchange coupling direction in spin valve supporting different pinned layers. Films were prepared on silicon or AltiC substrates at room temperature by the direct current magnetron sputtering system. Experimental results indicated that the exposure of the the spin valve to heat and magnetic field correlates with increases in cant.

In this work, the frequency response in magnetic tunnel junction (MTJ) heads was studied. Both stray capacitance and junction resistance, forming a low-pass-filter, have to be reduced to improve the cutoff frequency in MTJ heads. By employing an Ar gas cluster ion beam (GCIB) process, junctions grown on the magnetic shield show a resistance area product as low as 3.6 [Omega][micro][m.sup.2] and tunneling magneto-resistance over 14%. The dominant capacitance in common lead and shield MTJ heads was found mainly resulting from the shield-to-shield spacing, whose capacitance can be reduced by using an Si[O.sub.2] gap layer instead of [Al.sub.2][O.sub.3] layer and thus leading to an improved frequency response. Simple analysis indicates that a read amplifier design with low impedance could be helpful to realize a high data transfer rate, and a rate of around 800 Mbps for 100 Gbits/[in.sup.2] recording system can be thus expected. Index Terms--Common lead and shield, cut off frequency, data transfer rate, input impedance, magnetic recording/magnetic tunnel junction heads, stray capacitance.

Magnetic tunnel junction (MTJ) heads have been successfully fabricated using the free layer as flux guide to prevent electrical short during the definition of the air bearing surface (ABS). For a 6 Gbits/[in.sup.2] design, an output as high as 5740 [micro]Vpp was achieved for 3 mA sense current, and the output waveform was stable and noise free. Noise analysis confirmed that shot noise is prevailing in these MTJ heads, suggesting that the junction resistance has to be further reduced to challenge spin-valve heads in term of signal to noise ratio. Landau-Lifshitz-Gilbert simulations showed that for 20 Gbits/[in.sup.2] application, the flux guide height should not exceed 0. [micro]m. Index Terms--Magnetic recording/magnetic tunnel junction heads, front flux guide, shot noise, micromagnetic simulation.

A first attempt to longitudinally bias magnetic tunnel junctions for the application in magnetic read heads is presented. A design wherein the free layers uncovered lateral extensions is a promising candidate since good transfer curves could be simulated using either permanent magnets (PM) or AF slabs, deposited on top of the lateral extensions.