Why the dipolar response in dielectrics and spin-glasses is unavoidably universal

Abstract

Materials response to electric or magnetic fields is often dominated by the dynamics of dipoles in the system. This is for instance the case of polar dielectrics and many transition metal compounds. An essential and not yet well understood fact is that, despite their structural diversity, dielectric solids exhibit a striking universality of frequency and time responses, sharing many aspects with the behaviour of spin-glasses. In this article I propose a stochastic approach to dipole dynamics within which the “universal frequency response” derives naturally with Debye’s relaxation mechanism as a special case. This formulation reveals constraints to the form of the relaxation functions, which are essential for a consistent representation of the dynamical slowing-down at the spin-glass transition. Relaxation functions with algebraic-, and exponential-tails, as well as damped oscillations, are shown to have a unified representation in which the stable limit of the distribution of waiting-times between dipole flips determines the present type of dynamics.

A facile synthetic strategy to polysiloxanes containing sulfonyl side groups with high dielectric permittivity

“…It has been recently shown that the type of relaxation dynamics (i.e., how an induced polarization decays in time as the external field is switched off ) is analytically related to this slope. 37 Materials with α = 1 are well represented by Debye or Kohlrausch-Williams-Watt relaxation functions, featuring a standard (fast) exponential or stretched exponential time-decay. In these cases, there is an average relaxation time, well above which the system can be assumed to be at equilibrium.…”

Excellent microwave response derived from the construction of dielectric-loss 1D nanostructure

“…Different from conductors as well as semiconductors, the positive and negative charges are tied to the covalent bonds or ionic bonds, which are the so-called bound charges. In the microscopic field, the charges cannot migrate directionally and hence form a dipole moment, which is dielectric polarization [33][34][35][36]. In general, dielectric polarization comes from molecular polarization, atomic polarization, ion polarization, space charge polarization, and electron polarization [37,38].…”

Developing time to frequency-domain descriptors for relaxation processes: Local trends

“…Additionally, it would be of great utility and will provide a valuable set of techniques for employing in different analytical and laboratory procedures. For example, to accelerate the calculations or evaluate repeatedly such functions; in analysis and filtering of data by identifying the existence of superposed signals, or removing strong noise [48,49]; as well as to provide an exhaustive account of characteristic relaxation times -real or virtual- [19,34,41], and justify the underlying dominion behavior in diverse mechanisms [40,19,34,41,42,44,45,51,52].…”