Dielectric relaxation is the momentary delay (or lag) in the
dielectric constant of a material. This is usually caused by the delay in molecular
polarization with respect to a changing electric field in a dielectric medium (e.g. inside
capacitors or between two large
conducting surfaces). Dielectric relaxation in changing electric fields could be considered analogous to
hysteresis in changing
magnetic fields (for
inductors or
transformers). Relaxation in general is a delay or lag in the response of a
linear system, and therefore dielectric relaxation is measured relative to the expected linear steady state (equilibrium) dielectric values. The time lag between electrical field and
polarization implies an irreversible degradation of
free energy(G).
In
physics, 'dielectric relaxation' refers to the
relaxation response of a
dielectric medium to an external electric field of
microwave frequencies. This relaxation is often described in terms of
permittivity as a function of
frequency, which can, for ideal systems, be described by the
Debye equation. On the other hand, the distortion related to ionic and electronic polarization shows behavior of the
resonance or
oscillator type. The character of the distortion process depends on the structure, composition, and surroundings of the sample.
See also
★
Dielectric relaxation as a chemical rate process
★
Debye relaxation
★
Dielectric dispersion
★
Dielectric spectroscopy
★
Dielectric function