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Articles you may be interested inDual current-perpendicular-to-plane giant magnetoresistive sensors for magnetic recording heads with reduced sensitivity to spin-torque-induced noise

The femtosecond and picosecond dynamics of liquid aniline, nitrobenzene, and benzonitrile have been recorded through measurements of the optically heterodyne detected optical Kerr effect. A major part of the subpicosecond dynamics is assigned to librational motion. This assignment is supported by studies of para-substituted benzonitrile derivatives with differing moments of inertia. The librational frequencies of the three liquids are only weakly dependent on temperature but shift to lower frequency on dilution in inert solvents. The picosecond relaxation dynamics are well described by a biexponential function. The slowest relaxation time behaves, at least qualitatively, as predicted by hydrodynamic models of orientational diffusion. However, quantitative analysis suggests that some of the assumptions concerning the molecular shape or hydrodynamic boundary condition are inadequate to completely describe diffusive orientational motion in these liquids. Measurements of the slowest relaxation time as a function of dilution in nonpolar solvent showed that static orientational pair correlation is negligible in these liquids. The faster of the two picosecond exponential relaxation times could not be ascribed to orientational diffusion, and is instead proposed to arise from structural relaxation occurring on the picosecond time scale in these liquids.