An X-ray diffraction study of the short-range ordering in the soft-magnetic Fe–Si alloys with induced magnetic anisotropy

Atomic structure of the single crystals of the soft-magnetic alloy Fe–Si containing 5–6 at% Si with an induced magnetic anisotropy (IMA) of different degree was investigated using X-ray diffraction (XRD) method. The local structure of the iron alloys with 5–6 at% Si is shown to present in itself a structure characteristic of the atomic ordering of B2 type in combination with the ordering of atomic displacements from the sites of an ideal lattice. To a more detail, cells with B2 ordering compose pairs, triples, which are oriented along the easy magnetization axis 〈100〉. Under the heat treatment (annealing and cooling) in a DC saturating magnetic or a stress, load related, field, chains of two, or more, of the B2 cells joining in with each other have a mainly orientation along one of the easy axis, namely, that which makes a minimum angle with the direction of field or load application. After cooling, the formed anisotropic (spatially directed) short-range order is present at last due to low-diffusion mobility of atoms and, thus, becomes a reason for the anisotropy of magnetic properties.