Observation of Ferroelastic and Ferroelectric Domains in AgNbO₃Single Crystal

Compared to AgNbO3 based ceramics, the experimental investigations on the single crystalline AgNbO3, especially the ground state and ferroic domain structures, are not on the same level. Here, based on successfully synthesized AgNbO3 single crystal using a flux method, we observed the coexistence of ferroelastic and ferroelectric domain structures by a combination study of polarized light microscopy and piezoresponse force microscopy. This finding may provide a new aspect for studying AgNbO3. The result also suggests a weak electromechanical response from the ferroelectric phase of AgNbO3, which is also supported by the transmission electron microscope characterization. Our results reveal that the AgNbO3 single crystal is in a polar ferroelectric phase at room temperature, clarifying its ground state which is controversial from the AgNbO3 ceramic materials.