Bismuth layer-structured ferroelectrics with non-sheet-like polyhedral microstructures

Bismuth layer-structured ferroelectrics (BLSFs) are promising candidates for a variety of applications because of their high Curie temperature and environmentally benign nature as compared to their lead contained counterparts. Featured by the mica-like grain growth habit and spontaneous polarization along crystallographic a-b plane, it is difficult to obtain excellent ferroelectric properties for most of the BLSFs fabricated by the conventional ceramic route. Herein, a new approach is reported to obtain Bi2WO6 and Bi4Ti3O12 BLSF ceramics with non-sheet-like polyhedral microstructures. The intriguing ferroelectric hysteresis behavior, dielectric tunability, and domain structures are successfully observed. The Bi2WO6 ceramic with a unique single-domain structure in each grain shows a typical ferroelectric polarization-electric field hysteresis loop with a remnant polarization of similar to 17.8 mu C cm(-2) and a coercive field of similar to 43 kV cm(-1). These values have never been obtained in Bi2WO6 ceramics with sheet-like microstructure. The Bi4Ti3O12 ceramic with irregular-shaped and curved tiny domains exhibits an antiferroelectric-like behavior, which is significantly different from the reported Bi4Ti3O12 counterparts that have plate-like anisotropic grains. The present study would stimulate microstructure design and property modulation for other layer-structured materials.