Rhombohedral to orthorhombic morphotropic phase boundary in Y-doped BiFeO3 compounds determined by ab-initio calculations

SEPLIARSKY, MARCELO CLAUDIO; GRAF, MÓNICA ELISABET; LLOIS, ANA MARÍA; DI NAPOLI, SOLANGE; BARRAL, MARÍA ANDREA

Cancún

Congreso; XXVI International Materials Research Congress; 2017

The term "morphotropic phase boundaries" (MPB) is used to refer to the phase transition between two structurally dissimilar phases as a result of varying the composition or as a result of mechanical pressure. The compound Bi(1-x)Y(x)FeO3 presents two different structures at its end members and, therefore, might show a MPB. For oxide solid solutions having piezoelectric and ferroelectric functionalities, it is now established that many of the technologically useful electromechanical responses are highly enhanced at the characteristic composition that corresponds to the phase boundary. In this work we study, by means of ab initio calculations, the structural and electronic properties of the Y-doped BiFeO3 compound. We determine that there is a MPB at around x=0.19, when thestructure changes from R3c to Pnma, in agreement with a structural phase transition shown by reported experiments[1].[1] Saleh-Medina, L.; Jorge, G.; Negri, R. J. Alloys Compd. 2014, 592, 306.