“…Increased interest in this form is due from a fundamental point of view: that is associated with the miniaturization of dimensions and structural and magnetic properties, and with the wide possibilities of practical application of nanotubes; it is also due to the fact that many properties, particularly the magnetic texture and orientation of magnetic domains, are due not only to the phase composition, but also to the geometric characteristics of the structure [26,27]. Among the variety of different compositions of nanostructures, iron-containing (Fe 100-x Ni x ) nanostructures are incredibly interesting due to their magnetic characteristics and have found wide application in catalysis, magnetic carriers with ultra-high recording density, and biomedicine [28,29,30,31,32]. Despite the large number of papers devoted to the study of Fe 100-x Ni x nanostructures properties, interest in fundamentals of the influence of various factors on magnetic properties and ultra-fine magnetic texture has not faded [33,34,35,36].…”