One of today's tasks is the development of new strategies for the synthesis of ferromagnetic, superparamagnetic nanoparticles immobilized in a polymer or carbon nanostructured matrix, and studying of the possibility of influencing their structure and magnetic properties.When the critical parameter that determines certain phenomena (the size of magnetic domains, the characteristic length of exchange interactions, the length of magnetostatic interactions, etc.) becomes comparable to the particle size, nanoscale magnetic materials exhibit sharp (dramatic) variability of magnetic properties. Therefore, there is a need to develop new methods of synthesis, protection and certification of such nanosystems to synthesize promising magnetic materials using technologically controlled processes.The encapsulation of metal nanoparticles into carbon chemically inert graphite like shells allows the synthesis of new generation materials to begin. Magnetic nanoparticles occupy an important place among these materials and such nanoparticles, which can be technologically important magnetic materials, will be investigated in this paper.The formation of nanocomposites, the production of nanoparticles of the same size and, accordingly, with reproducible properties, is one of the main technological tasks of this research. Methods of obtaining, which allow us to precisely control the size of particles are continuously improved. Magnetic nanostructured materials with unique electrical, mechanical, catalytic, optical and, moreover, specific magnetic properties, make it possible to constantly expand their fields of application in computer science, catalysis, for sensors production, in medicine and in biology.The correlation between nanostructure and magnetic properties allows us to offer different types of magnetic nanostructures: (1) systems with isolated particles, whose unique magnetic properties derive from decreasing sizes of components; (2) ultrafine particles with a cortical structure; (3) materials in which magnetic interaction is the dominant property; (4) nanocomposites, which consist of magnetic particles encapsulated in a chemically inert matrix. The magnetic properties in this case are determined by the ratio of volume fractions of magnetic particles and the matrix.In this work, we studied the effect of an external magnetic field on the formation and phase composition of iron particles synthesized in an arc discharge in a liquid phase. These products can be technologically important magnetic materials.