Nucleation and wall motion in graded media

Droplet nucleation and domain wall motion in a bounded interval.

We study a spatially extended model of noise-induced magnetization reversal: a classical Ginzburg-Landau model, restricted to a bounded interval and perturbed by weak spatiotemporal noise. By adapting the Coleman-Langer approach to false vacuum decay, we determine the dependence of the activation barrier and Kramers rate prefactor on the interval length. As it increases, a transition between ac...

Dynamics of magnetic domain wall motion after nucleation: dependence on the wall energy.

The dynamics of magnetic domain wall motion in the FeNi layer of a FeNi/Al2O3/Co trilayer has been investigated by a combination of x-ray magnetic circular dichroism, photoelectron emission microscopy, and a stroboscopic pump-probe technique. The nucleation of domains and subsequent expansion by domain wall motion in the FeNi layer during nanosecond-long magnetic field pulses was observed in th...

Observation of unequal activation volumes of wall-motion and nucleation processes in Co/Pd multilayers.

We report the difference in activation volumes of wall-motion and nucleation processes in Co/Pd multilayers. Each activation volume was estimated from field dependence of wall-motion speed and nucleation rate, obtained by real-time domain imaging using a magneto-optical Kerr effect microscope. Delicate analysis shows that the two activation volumes are generally unequal and the ratio between th...

Functionally Graded Media

the study of bright and surface discrete cavity solitons dynamics in saturable nonlinear media

امروزه سالیتون ها بعنوان امواج جایگزیده ای که تحت شرایط خاص بدون تغییر شکل در محیط منتشر می-شوند، زمینه مطالعات گسترده ای در حوزه اپتیک غیرخطی هستند. در این راستا توجه به پدیده پراش گسسته، که بعنوان عامل پهن شدگی باریکه نوری در آرایه ای از موجبرهای جفت شده، ظاهر می گردد، ضروری است، زیرا سالیتون های گسسته از خنثی شدن پراش گسسته در این سیستم ها بوسیله عوامل غیرخطی بوجود می آیند. گسستگی سیستم عامل...