First-principles study of spontaneous polarization in multiferroicBiFeO3

Abstract

The ground-state structural and electronic properties of ferroelectric BiFeO 3 are calculated using density functional theory within the local spin-density approximation ͑LSDA͒ and the LSDA+ U method. The crystal structure is computed to be rhombohedral with space group R3c, and the electronic structure is found to be insulating and antiferromagnetic, both in excellent agreement with available experiments. A large ferroelectric polarization of 90-100 C/cm 2 is predicted, consistent with the large atomic displacements in the ferroelectric phase and with recent experimental reports, but differing by an order of magnitude from early experiments. One possible explanation is that the latter may have suffered from large leakage currents. However, both past and contemporary measurements are shown to be consistent with the modern theory of polarization, suggesting that the range of reported polarizations may instead correspond to distinct switching paths in structural space. Modern measurements on well-characterized bulk samples are required to confirm this interpretation.

Magnetoelectric Ordering of BiFeO3 from the Perspective of Crystal Chemistry

“…Analysis of the partial density of states reveals mixing of the Pb 6s with the oxygen 2p electronic states indicating that the classical theory of hybridization of the lead 6s and 6p orbitals is incorrect and that the lone pair is the result of the lead-oxygen interaction. These two very studies [41,64] formed a basis for the explanation of the emerging of ferroelectricity in Bi and Pb perovskites given by Hill [37], Neaton [65], and Ravindran [42]. They demonstrate that the ferroelectricity is originating from the distortion of Bi(Pb)-O coordination environment as a result of the stereochemical activity of the lone pair on Bi(Pb).…”

Crystallographic and Magnetic Structure of the Perovskite-Type Compound BaFeO2.5: Unrivaled Complexity in Oxygen Vacancy Ordering

“…Perovskite-type compounds have many applications, ranging from electrode materials in solid oxide fuel cells (e. g. La 1-x Sr x CoO 3-d 1 and La 1-x Sr x FeO 3-d 2, 3 ), ferroelectrics (e. g. BaTiO 3 4 ), multiferroics (e. g. BiFeO 3 , Bi 1-x A x FeO 3 -d , A = Ba, Sr, Ca, Pb [5][6][7][8][9][10][11] ) to materials with interesting magnetic properties (e. g. ferromagnetic BaFeO 3 12 (by oxidation of BaFeO 2.5 using O 3 ) as compared with antiferromagnetic BaFeO 2 F compounds [13][14][15] ). The possibility of vacancies on the anion sublattice gives rise to many of the properties of such compounds, including ionic (anionic) conductivity (facilitated by anion vacancies) and electronic conductivity (due to mixed valence) and magnetic order which is often promoted via superexchange interactions via the anions.…”

Rare earth (La) and metal ion (Pb) substitution induced structural and multiferroic properties of bismuth ferrite

“…BFO has a rhombohedrally distorted perovskite structure (space group R3c) with high Curie temperature (T C  1100 K) and antiferromagnetic Néel temperature (T N = 675 K) with a spatially modulated spiral spin structure [3][4][5]. The literature witnesses that the A-site substitution in BFO has been suggested as the most effective way to reduce the impurity phases and enhance magnetoelectric coupling constant by creating the lattice strain due to the ionic size mismatch between hosts and substituting cations [6][7][8][9][10].…”