Distinctive contributions to dielectric response of relaxor ferroelectric lead scandium niobate ceramic system

Abstract

Dielectric properties of (PSN) ceramic system, prepared from mechanochemically activated powder, were studied in a broad temperature range of 150–750 K. Various distinctive contributions were recognized in the detected reponse. A typical relaxor dispersive maximum, accompanied by a sharp dielectric anomaly showing a hysteretic behavior, reveals that developed disordered PSN ceramics undergoes a spontaneous relaxor‐to‐ferroelectric phase transition, even in zero electric field. At high temperatures, a strong dielectric dispersion due to the Maxwell–Wagner‐type contributions of interface layers between the sample and contacts governs the detected response above 500 K. The intrinsic high‐temperature dielectric response follows, however, the universal scaling rather than the classical mean‐field behavior. The latter can be rejected on the confidence level better than 99% according to the F‐test and, furthermore, the analysis revealed a critical exponent that indicates a critical behavior associated with universality classes typically found in spin glasses. Finally, nearly perfect agreement between the fitting parameter of K (obtained by analysis in the interval of 600–775 K) and the experimentally detected value of this relaxor‐to‐ferroelectric phase transition temperature manifests that the low‐temperature fingerprint behavior can be observed at much higher temperatures, well above the dispersive relaxor dielectric maximum.