phenomenon in which the dielectric is limited to the amount of displacement of related charges, or there is a turn of electric dipoles in physics received the name of the polarization of dielectrics.During this process may occur either spontaneously due to internal causes, or by external forces, especially of the electric fields.
Physical and mathematical reflection of the process is characterized by a polarization vector is the dipole moment, which is considered in relation to the magnitude of the volume of the dielectric.Quite often in the physical context using simple term - polarization.This parameter is used not only to reflect the macroscopic state.It can be used to describe any phenomena with properties that characterize the polarization of dielectrics.
From this statement, we can formulate a common symptom of the phenomenon.Such a state of the dielectric in which it detects the presence of the dipole moment at each point of its volume, and characterizes the polarization of dielectrics.
This phenomenon is ambiguous in nature.There are such types as the induced polarization of dielectrics, that is caused by the influence of external electric fields, spontaneously formed in the absence of external agents of polarization, mechanical (ferroelectric) is formed by the action of mechanical pathogens, heat, arising under the influence of temperature fluctuations.
peculiarity of polarization as a physical phenomenon is that it has virtually no effect on the value of the total charge of a homogeneous dielectric, whatever point of its volume is not selected.At the same time, polarization occurs in the formation of bound charges on the dielectric surface.These charges are the source of additional field with a certain tension, a vector which is directed against the vectors of the external field.
important in the matter stands and classification of polarization of dielectrics according to its own mechanisms.In this aspect, it includes such types:
- Migration is characteristic of materials in the structure which are clearly distinct layers with different conductivity.Such polarization is characterized by delayed action;
- electron polarization is to move the shells of atoms under the influence of external electric fields.This - the fastest type of polarization;
- ion is characterized by the same factors as the electron, but in this case there is no displacement of the shells of the atoms, and the movement of units of the crystal lattice structure of the substance;
- dipole, or as it is called the polarization orientation is characterized by a significant loss, the cause of which is a lot of energy to overcome the internal connections in the dielectric.For the orientation of the polarization of dielectrics characterized by the phenomenon of well-defined orientation of the dipoles;
- electron relaxation is characterized by the presence of a specific orientation of defect electrons;
- ion relaxation dielectric polarization manifested in the movement of ions, which have weak internal connections are not fixed and stable in the crystal lattice sites of the structure of matter;
- structure is also reflected in a certain orientation of the dielectric elements, but in this case, those elements are the various impurities, which contains the substance of the dielectric.This polarization occurs more slowly;
- spontaneous (spontaneous) is observed at a very high dielectric constant parameters, they are called ferroelectrics;
- is characterized by the coincidence of resonance frequencies of electrons dielectric frequency of exposure to a field, here, in fact, is the name.
As a rule, in all cases, except for the resonance polarization, its value reaches a maximum in static fields.
