On the fine structure of X-ray topographic images of 90° ferromagnetic domain walls in Fe–Si

Abstract

Fringe patterns in X‐ray topographic images of 90° ferromagnetic domain walls in Fe–3 wt% Si single crystal specimens prepared as plates parallel to (001) have been investigated with a wide variation of experimental conditions including changes of specimen thickness (in the range 75 to 340 μm), Bragg reflecting plane, order of reflection and X‐ray wavelength (AgKα, MoKα, and CoKα). It is demonstrated that the fringes are dominantly images of real internal fine structure of the 90° walls rather than an X‐ray interference effect, i.e. fault surface fringes. The fringe pattern results from the walls having a zig‐zag structure: walls of mean orientation (110) being composed of facets roughly parallel to (111) and (111). X‐ray topographs enable the mean orientation of the walls to be measured (it may depart by up to 10° from (110)), and the zig‐zag period to be determined (mean value 13 μm) at points within the crystal.

Decomposed bloch walls in iron

“…The knowledge of the magnetoelastic term allows a complete calculation of the energy of the wall and this calculation shows that the equilibrium configuration is the zig-zag shape. We then deduced the periodicity and the angle of the zig-zag which are in good agreement with the experimental results obtained so far [1,2,3].…”

“…On such samples, with T = 100 gm and 300 um respectively, Polcarova and Lang [2] find an average value of 13 gum for the periodicity of the zig-zag in both cases. No accurate measurement is made concerning the angle 9.…”

“…The equi -e+13 and -e+23 curves are drawn in figures 6 and 7 assuming qJ = 620 30' and d = 13 pm according to the equilibrium values given by Kaczer [3] and Polcarova [2]. On the other hand, for a given value of d and T, the strains are independent of the number of zig-zags taken between A and F ( Fig.…”

“…Introduction. -Zig-zag 900 (110) Bloch walls in iron were first observed by Chikazumi and Suzuki [1] by Bitter pattern techniques and later by Polcarova and Lang [2] using X-ray topography. The zig-zag shape occurs in wall segments symmetrically inclined with respect to the (110) plane.…”

On magnetic domain configurations in single-crystal, (112)-orientation plates of iron-silicon alloy: some X-ray topographic observations and their interpretation

“…Most published X-ray topographic studies of magnetic domains in Fe-Si have been performed on specimen plates parallel to at least one direction of easy magnetization; and in (001) plates a variety of phenomena have been investigated, e.g. the zig-zag fine structure of 90° domain walls (Polcarova & Kaczer 1967;Polcarova & Lang 1971) and the strainfields of 'fir tree' closure domains (Miltat 1976). However, on specimens containing no direction of easy magnetization there is an important work combining Bitter pattern, Kerr effect and X-ray topographic observations on (lll)-orientation plates (Labrune & Kleman 1973).…”