Nonequilibrium kinetics of the electron–phonon subsystem can give rise to electric- and magnetic-plasticity effects in crystals in alternating electric and/or magnetic fields

Abstract

Kinetic processes in magnetic crystals in an alternating magnetic field and/or a pulsed electric field are studied theoretically, experimentally, and numerically to establish the prime mechanisms by which they influence the structure and the mechanical, dissipative, and magnetic characteristics of crystals. The specific materials studied are severly strained ferritic pearlite steel 15Kh2NMFA and nickel. The paper presents a systematic kinetic analysis of the nonequilibrium dynamics of the electron–phonon subsystem of a magnetic crystal in an electric field. Our proposed method that underlies the analysis solves the system of Boltzmann equations for the electron and phonon distribution functions numerically without expanding the electron distribution function in a power series of the phonon energy. It is shown that an electronic subsystem excited by an electric field transfers energy to the phonon subsystem and thereby massively produces short-wave phonons which act strongly on lattice defects (such as point and linear ones and phase boundaries) and thus redistribute and decrease their density, as well as providing damage healing, decreasing local peak stresses, and reducing the degradation level of construction materials properties. It is found that, under the action of an induction electric field, the electron distribution function becomes nonequilibrium near the Fermi level energy and, as a result of electron–phonon collisions, transfers significant energy to the phonon subsystem, resulting in forming a nonequilibrium phonon distribution function. Based on modified Granato–Lücke and Landau–Gofman models, it is shown, using the calculated phonon distribution function, that the action of phonons on dislocations is much stronger than it would be in the case of thermodynamic equilibrium at the experimentally measured sample heating by 12 K.