Reorientation of magnetic dipoles at the antiferroelectric-paraelectric phase transition ofBi1−xNdxFeO3<

Mn substitution-modified polar phase in the Bi1−xNdxFeO3 multiferroics

“…The situation drastically changes with further increase of the Mn content. Indeed, polar x ¼ 0.15 sample demonstrates the field dependence of magnetization characteristic of the Bi 1 x Ln x FeO 3 compounds in the doping-induced nonpolar wF phase 16,20,[39][40][41] ( Fig. 5(a)).…”

Temperature dependent piezoelectric response and strain–electric-field hysteresis of rare-earth modified bismuth ferrite ceramics

“…One explanation may lie in the restriction of in-plane strain by the substrate in the epitaxial thin-film [46][47][48] . There are considerable differences in the lattice parameters of R3c and Pbam phases in RE-BFO compositions, discussed in detail by Levin et al, resulting in a difference of the unit cell volume < 1% 49 . Thus, for RE-BFO compositions with complex R3c-Pbam phase coexistence, the epitaxial stress of thin films could conceivably moderate the phase composition and create the incongruity observed between the phase assemblages in ceramics and epitaxial thin films with the same composition.…”

“…At the T c the phase changes from rhombohedral R3c to orthorhombic Pbnm in the BGFO and BDFO ceramics, and from a majority phase orthorhombic Pbam (with coexisting rhombohedral R3c) to orthorhombic Pbnm in BSFO (see Fig. 1 and ref 11,29,49 ). The phase transitions R3c-to-Pbnm and Pbam-to-Pbnm involve different rearrangements of the cation displacements, but have been shown to exhibit clear similarities, with similar contraction of the FeO 6 octahedral volume and corresponding reorientation of the oxygen octahedra, as well as similar abrupt changes of the unit cell volume < 1% 49 .…”

“…1 and ref 11,29,49 ). The phase transitions R3c-to-Pbnm and Pbam-to-Pbnm involve different rearrangements of the cation displacements, but have been shown to exhibit clear similarities, with similar contraction of the FeO 6 octahedral volume and corresponding reorientation of the oxygen octahedra, as well as similar abrupt changes of the unit cell volume < 1% 49 . This volume change is relatively large compared to other polar-to-non-polar transitions in ferroelectrics where the non-polar phase is cubic, for example in PZT a volume change around ~0.5% may be expected depending on the precise composition (i.e.…”

Maghemite-like regions at the crossing of two antiphase boundaries in doped BiFeO3

“…This has included the discovery of the stabilisation of a super-''tetragonal'' phase with a c/a value of *1.25 using compressive substrate induced strain in epitaxial growth, 6 as well as the discovery of a complex phase diagram on doping on the A site with rare earth ions. [7][8][9][10] Additional doping of Ti on the B site can be performed to minimise the conductivity and allow the ferroelectric properties to be fully accessed. 11 Recently, we showed that co-doping with Nd and Ti can also create novel defects and structures in BiFeO 3 including Nd and O rich nanorods, 12,13 and planar and stepped antiphase boundaries (APBs), based on Ti and Fe rich structural units respectively.…”