Admittance spectroscopy of glassy behavior in relaxor ferroelectrics

Glass like behaviour in Pb(Mg1/4Cd1/12Nb2/3)O3 relaxor

“…The broad distribution of sizes of polar clusters gives rise to the broad distribution of relaxation times because of relaxation time s i (=R i C i ) is proportional to the size of polar cluster. All these series elements are in parallel and the assemblage of all these polar clusters makes the relaxor ferroelectrics to follow the glassy relaxation behaviour [26]. Therefore, a relaxor ferroelectric system could be considered as the sum of responses of relaxators in widely distributed spectrum of their relaxation times.…”

“…It is believed that the glassy relaxation is the basic and key character of relaxor ferroelectrics [15,25,26]. The glassy relaxation characterizes a broad and equal probability distribution of relaxation times [25,26]. For a linear relaxation processes of the type modeled by the series RC-branch, the principle of superposition allows the complex admittance to be described as:…”

“…The value of f 0 is found to be in the optical frequency range of the lattice vibrations. It is believed that the glassy relaxation is the basic and key character of relaxor ferroelectrics [15,25,26]. The glassy relaxation characterizes a broad and equal probability distribution of relaxation times [25,26].…”

“…The distribution should normalize m l 0 gðs; T Þds ¼ 1. The real and imaginary part of admittance can be written as [26] …”

“…Based on this analogy, the relaxor system could be considered as a dipolar glass based on freezing of superparaelectric clusters [1,14]. Further, it is believed that the assemblage of the relaxor elements with broad distribution of relaxor times give rise to the glassy behaviour of the relaxor ferroelectrics [15,25,26].…”