Material considerations for vertical Bloch lines direct observation and dynamical study

The authors report on a materials growth study undertaken to clarify the origin of vertical Bloch lines contrast by direct optical observation in dark field on bubble garnet samples. The authors' initial guess (a large Faraday rotation) was shown to be incorrect. Rather, the influence of a low quality factor (the ratio of uniaxial energy constant to the demagnetizing energy) was detected. This agrees with a model wherein the wall tilts out of the vertical plane, at the line position. A control of lines observation is thus possible. The authors demonstrate it for specific samples grown to be put in a bias field gradient system stabilizing one single wall.<
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