Results 1 - 10 of 14176
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[en] Orientation changes in sol-gel derived (40%)Pb(Sc1/2Nb1/2)O3-(60%)PbTiO3 (PSNT(40/60)) thin films on two different kinds of Pt bottom electrodes were investigated. PSNT thin films grown on the Pt/TiO2/SiO2/Si substrate with a high degree of (111) Pt preferred orientation showed predominant (100) orientation while the others on the Pt/Ti/SiO2/Si substrate with a lesser degree of (111) preferred orientation had random orientation. The effects of these two different substrates were show through the crystallographic orientation of the films in correlation with the microstructure and orientation Pt-bottom-electrode
[en] Coalescence and impingement, which in the time domain give rise to completely different kinetics for the density of islands, are shown to lead to common kinetics in the domain of the fraction of covered surface in the case of thin-film growth after simultaneous nucleation. This result allows one to treat the more involved intermediate case (partial coalescence) in a rather straightforward way. On this basis experimental data taken from the literature are discussed and reanalyzed in order to evaluate the saturation density of the nuclei
[en] To investigate the influence of strip width and inter-strip separation on the AC loss, arrays of parallel strips with different widths and separations were prepared. Studies on the hysteresis-loss characteristics of multifilamentary YBCO films were performed. The local magnetic field due to magnetization currents is measured by a scanning Hall probe microscope. Based on these results a conceptual design for a low loss YBCO coated conductor is suggested.
[en] The dielectric loss in amorphous, thin-film oxide insulators produces a real part of the ac conductivity σ prime (ω) that scales as ωs with s∼1. Conventional models explain this frequency dependence by hopping or tunneling of charge between neighboring defect sites. These models fail at low temperatures since they predict that σ prime should vanish at T=0. We observe that the ac conductivity of Ta2O5, ZnO, and SiO2 has a nonzero extrapolated value at T=0. We propose that this behavior is consistent with the predictions of a Coulomb glass, an insulator with a random distribution of charged defects. [copyright] 2001 American Institute of Physics
[en] The precessional switching process in magnetic recording thin films is investigated by means of micromagnetic simulations. The uniform mode theory is used to predict the right time instant to switch off the field and the time tolerance which still allows successful switching. This analysis is performed for different values of applied field and anisotropy constant. We verified that the uniform mode theory provides accurate information about the tolerance on the switching time for moderately soft materials
[en] The giant magnetoimpedance (GMI) effect of controlled-inclination magnetic stripe domain for a thin-film GMI sensor is investigated. The inclined stripe domain structure has an inclined angle of domain walls against the transverse direction of the rectangular-strip element. It is obtained that GMI profile changes from a profile with a dip point at the zero magnetic field to a profile with one maximum impedance only at the zero field at an angle of 70 deg. . In the case of GMI profile with a dip point, increasing the inclination angle decreases the bias field. This reduction of the bias field more than triples the sensor gain. An excellent linear property extending for wide range is obtained. A steplike impedance change property is also realized by this method
[en] For ac applications a detailed understanding of the ac power losses associated with different conductor configurations is of crucial importance. YBCO thin films were divided into parallel filaments with widths of 1, 2, and 4 mm to reduce hysteresis losses. The measured hysteresis losses show a linear relationship between the strip width and hysteresis loss as anticipated. The influence of different inter-filament separations on the hysteresis loss is investigated.
[en] We study theoretically the behavior of vortices in a thin film superconductor placed close to a soft magnetic film. It is shown that the field from the vortex induces a magnetization distribution in the soft magnetic film, thus modifying the fields and vortex interactions. We suggest that the interaction between two otherwise identical vortices is attractive at short distances, but repulsive at larger distances. This is in contrast to the case without the soft magnetic film, where the force is always repulsive
[en] This paper investigates the influence of sharp concentration gradients and/or chemical potentials on the nucleation of intermediate phases during solid state reactions between elements with limited solubility. These factors would not appear to have any significant influence on first intermediate phase nucleation. On the other hand, for the second and subsequent phases, thermodynamic suppression (in addition to the kinetic factor) of nucleation can be quite considerable and may well be the reason for sequential phase formation in thin films. Thermodynamic suppression criteria for intermediate phase nucleation are proposed