Barkhausen noise probe of the ferroelectric transition in the relaxor PbMg1/3Nb2/3O

Abstract

Abstract:Barkhausen current noise is used to probe the slow field-driven conversion of the glassy relaxor ferroelectric state to an ordered ferroelectric (FE) state. The frequent presence of distinct micron-scale Barkhausen events well before the polarization current starts to speed up shows that the process is not a conventional nucleation-limited one. The prevalence of reverse switching events near the onset of the rapid part of the transition strongly indicates that electric dipole interactions play a key role. The combination of Barkhausen noise changes and changes in the complex dielectric response indicate that the process consists of an initial mixed-alignment domain formation stage followed by growth of the domains aligned with the applied field.

Avalanches in ferroelectric, ferroelastic and coelastic materials: phase transition, domain switching and propagation

“…Similar approaches were used to study relaxor ferroelectrics and the behaviour of polar nanoregions in Pb(Mg 1/3 Nb 2/3 )O 3 [46] and 0.88Pb(Mg 1/3 Nb 2/3 )O 3 -0.12PbTiO 3 (PMN-PT) [47]. Under a sinusoidal electric field of maximum amplitude 130 V cm À1 , jumps in current were observed in the paraelectric phase of Pb(Mg 1/3 Nb 2/3 )O 3 , where macroscopic ferroelectric domains are absent.…”

“…From the size of the jumps, it is estimated that switching events involve more than a single polar nanoregion. Complementary measurements were performed under dc-electric field (instead of ac-electric field) and thus in the ordinary ferroelectric regime where jumps in current are induced by the motion of macroscopic domains [47][48][49].…”