This paper presents the investigation of the probability of changes in the magnetic properties of nanomaterials in strong fields of charged particles, neutrons and gamma rays. CoxNi1-xFe2O4 nanoparticles were obtained by the hydrothermal method using polyethylene glycol. Investigation of the properties of this material showed that its magnetic properties depend on the concentration of Со2+. In this work it is shown that the nuclear reactions taking place in the crystal lattice sites can change the relative concentration of the components of test material and, accordingly, its magnetic properties, including the coercive force.