An exactly solvable model for the results of small-angle scattering of neutrons by Bloch walls in bulk iron single crystals

The refraction and reflection of neutrons by Bloch walls, which are regarded as gradual transitions from one magnetization direction to the other, are described both theoretically and experimentally. The theory shows some modification of the simple refraction model: (i) the lack of the usual critical angle of total reflection, (ii) the necessary distinction between beams with and without spin flip, (iii) the possibility of splitting the transmitted beam into three beams every time one wall is traversed. This behaviour depends strongly on the wall thickness. Some experiments are described which verify these theoretical predictions and enable the wall width to be measured