Coexistence of multi-scale domains in ferroelectric polycrystals with non-uniform grain-size distributions

Magnetoelectric coupling at the domain level in polycrystalline hexagonal ErMnO3

“…The spatial resolution of Rcos# (amplitude R and phase # of the piezoelectric response) allows to distinguish domains with an antiparallel orientation of the ferroelectric polarization, while the grain boundaries separating grains of different crystallographic orientations are displayed by dashed white lines as explained in detail elsewhere. [22][23][24][25] The PFM image reveals a pronounced contrast, corresponding to the characteristic ferroelectric domain structure of polycrystalline h-ErMnO 3 , featuring a mixture of vortex-and stripe-like domains that form at T c % 1420 K. 26,27 To explore the low-temperature response of our polycrystalline h-ErMnO 3 sample, we measure the macroscopic dielectric permittivity as a function of temperature over 2-250 K for a range of frequencies from 1 to 10 3 Hz. As displayed in Fig.…”