Retarded Electromagnetic Interaction and Origin of Non-linear Phenomena in Ferroelectrics, Ferromagnetics and Optics

Abstract

The non-linear relations between polarization strength and electric field strength for ferroelectrics, as well as magnetization strength and magnetic field strength for ferromagnetics, can be achieved by introducing retarded electromagnetic interactions. The electric and magnetic hysteretic loops, as well as polarization and magnetization curves, can be described well based on soft mode theory in the alternating electromagnetic fields of low and medium frequencies. The fundamental phenomenological formula in non-linear optics can also be obtained in high frequency fields. The results show that all of these non-linear phenomena originate from retarded electromagnetic interaction.