1 research outputs found
Spontaneous and induced ferroelectricity in the BiFe1−xScxO3 perovskite ceramics
High-pressure synthesis method allows obtaining single-phase perovskite
BiFe1-xScxO3 ceramics in the entire concentration range. As-prepared compositions with x from 0.30 to 0.55 have the antipolar orthorhombic Pnma structure
but can be irreversible converted into the polar rhombohedral R3c or the polar
orthorhombic Ima2 phase via annealing at ambient pressure. Microstructure
defects and large conductivity of the high-pressure-synthesized ceramics make it
difficult to study and even verify their ferroelectric properties. These obstacles can
be overcome using piezoresponse force microscopy (PFM) addressing ferroelectric behavior inside single grains. Herein, the PFM study of the BiFe1-xScxO3
ceramics (0.30 ≤ x ≤ 0.50) is reported. The annealed samples show a strong PFM
contrast. Switching of domain polarity by an electric field confirms the ferroelectric nature of these samples. The as-prepared BiFe0.5Sc0.5O3 ceramics
demonstrate no piezoresponse in accordance with the antipolar character of the
Pnma phase. However, application of a strong enough electric field induces
irreversible transition to the ferroelectric state. The as-prepared BiFe0.7Sc0.3O3
ceramics show coexistence of ferroelectric and antiferroelectric grains without
poling. It is assumed that mechanical stress caused by the sample polishing can
be also a driving force of phase transformation in these materials alongside
temperature and external electric field.publishe