Rusakov V. Penetration of the magnetic field into metal oxide compounds and niobium alloys: the role of magnetic pre-history

The behavior of metal - oxide compounds and niobium alloys is studied in the external magnetic field at varied temperature. The influence of different physical parameters, studied materials and exposures has been investigated with respect to the dynamics of thermo-magnetic instabilities in the materials of varied structures and compounds. The areas of stability of the critical state and the influence of the magnetic pre-history on the emergence of thermo-magnetic instabilities are defined as well as the dynamics of thermal and magnetic relaxation processes with the use of magnetic, tensiometric, impedance and resistance low-temperature measurements, mathematic models and the methods of the theory of stability. The integrated experimental and theoretical investigation of a wide class of the materials has been carried out. A set of new phenomena has been found out such as: giant magnetostriction and the jumps of magnetostriction in niobium compounds, oscillation processes in a vortex structure, the existence of a threshold of the flux penetration etc. The results of the experiments are well clarified using the suggested theoretical models. Different parameters of the studied materials have been calculated basing on the experimental data. The obtained results can be used in the course of theoretical analysis in solid state physics and the physics of superconductivity, in the area of energy saving technologies and transport that is very important with respect to technical use and in the lectures of special courses of the abovementioned branches of science.