Structural, morphological and piezoresponse studies of Pr and Sc co-substituted BiFeO₃ ceramics

Abstract

Abstract Pristine (BiFeO 3 ), Pr and Sc co-substituted Bi 0.9 Pr 0.1 Fe 1− x Sc x O 3 (0.01 ⩽ x ⩽ 0.07) ceramics have been investigated for their structural (including x-ray diffraction and Raman), morphological and piezoresponse behaviour. Secondary phases observed in pristine BiFeO 3 (BFO) ceramic were significantly suppressed in the co-substituted samples. Grain size decreased in the co-substituted samples. Raman study revealed ten active phonon modes which remained almost invariant with co-substitution. Out-of-plane piezoresponse (OPP-PFM) exhibited negative self-polarization effect in the virgin state (without any poling) which has been explained in terms of built-in electric field. The self-polarization effect is largest in 3% Sc co-substituted sample. Poling with ±30 V dc voltage demonstrated both positive and negative domains. Maximum difference in the peak values (from histograms) of such opposite domains was observed in the Bi 0.9 Pr 0.1 Fe 0.99 Sc 0.01 O 3 sample. Information from local measurements (such as PFM) should be useful in deciding such multiferroic materials for device application.