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Unpredictable mechanical stresses that occur during the operation of hard disk drives can degrade the recorded signal. On the basis of a micromagnetic analysis and the calculated stress field during head-disk impact, inverse magnetostriction effects in longitudinal recording thin film media are considered and demagnetization due to head-disk impact is simulated numerically. Thin film media are modeled as planar hexagonal arrays of hexagonally shaped grains. The computation uses the conjugate gradient algorithm to minimize the variation of the total energy. In particular, the effect of the stress on the relaxation process is investigated. Also the change in the remanent magnetization due to repetitive head-disk impacts is calculated. We obtained results indicating that the effect of the impact stress during dynamic loading is not so significant as to cause data loss during operation for the longitudinal thin film media.

This paper presents an approach to achieve an optimal air bearing surface (ABS) design by using the reduced-basis concept that can effectively reduce the number of design variables. A multicriteria optimization problem is formulated to meet both the desired flying characteristics over the entire recording band and the fast takeoff performance at the landing zone. The optimal solutions of the sliders, whose target flying heights are 12 and 9 nm, are obtained. Due to its efficiency, our proposed method achieves the optimum solution with less than one-tenth of the effort for the conventional optimization method. Index Terms--Air-lubricated slider bearing, optimum design, reduced-basis concept.

Flying attitudes of the slider, which are flying height, pitch, and roll, are affected by air-flow velocity, skew angle, and manufacturing tolerances. In the traditional design process of air-bearing surfaces, we have considered only the steady state flying attitude over the recording band. To reduce the flying height variation during track seek as well as in steady state, we design a new shape for air-bearing surfaces. An optimization technique is used to improve the dynamic characteristics and operating performance of the new air-bearing surface shapes. The quasistatic approach is used in the numerical simulation of the track seek operation because the skew angle effect dominates the inertial effect even at high seek velocities. The perturbation method is applied to the lubrication equation to obtain the air-bearing stiffness. We employ the method of modified feasible directions and use the weighting method to solve the multicriteria optimization problem. The optimally designed sliders show enhanced flying and dynamic characteristics. The steady state flying heights are closer to the target values and the flying height variations during track seek operation are smaller than those for the original ones. The pitch and roll angles are kept within suitable ranges over the recording band during track seek operation as well as in steady state. The air-bearing stiffnesses of the optimally designed sliders are larger than those of the original ones. [DOI: 10.1115/1.1308031]

We present optimum results of the two sub-ambient pressure shaped rail sliders. The goal of optimization is to meet the desired flying characteristics over the entire data zone at sea level as well as at the 5000ft. altitude condition. The design variables are the geometry of ABS, the recess depth, and the location of the pivot. The method of feasible direction is utilized to find the optimum designs. The optimally designed sliders show the enhanced flying characteristics along with the less deviation at high altitude condition. Index Terms--Air bearing slider, flying attitude, high altitude condition, optimum design.

We have explored the effect of post-annealing on the electrical properties of an indium gallium zinc oxide (IGZO) transistor with an Al2O3 bottom gate dielectric, formed by a sol–gel process. The post-annealed IGZO device demonstrated improved electrical performance in terms of threshold variation, on/off ratio, subthreshold swing, and mobility compared to the non-annealed reference device. Capacitance–voltage measurement confirmed that annealing can lead to enhanced capacitance properties due to reduced charge trapping. Depth profile analysis using X-ray photoelectron spectroscopy proved that percentage of both the oxygen vacancy (VO) and the hydroxyl groups (M–OH) within the IGZO/Al2O3 layers, which serve as a charge trapping source, can be substantially reduced by annealing the fabricated transistor device. Furthermore, the undesired degradation of the contact interface between source/drain electrode and the channel, which mainly concerns VO, can be largely prevented by post-annealing. Thus, the facile annealing process also improves the electrical bias stress stability. This simple post annealing approach provides a strategy for realising better performance and reliability of the solid sol–gel oxide transistor. [ABSTRACT FROM AUTHOR]