Controllable defect driven symmetry change and domain structure evolution in BiFeO₃with enhanced tetragonality

Abstract

True tetragonal BiFeO3 with c/a ratio of ∼1.3.

Strain Engineering of Epitaxial Oxide Heterostructures Beyond Substrate Limitations

“…4c and 4d) reveals the realization of true T phase (not MC phase) BFO via this proposed method. Although the nearly tetragonal phase on LAO 58 and YSZ 59 substrates by biaxial strain and true T phase on LAO by chemical doping 49 or uniaxial strain [37][38][39] have been reported, here we obtain true T phase BFO using biaxial strain. RSM data of 50 nm-thick BFO on STO, NSO and LSAT (as shown in Fig S4, Fig S5 and Fig S6, respectively) further demonstrate the coexistence of R and T-like phases in agreement with AFM measurements (Fig.…”

Applications of Ion Beam Irradiation in Multifunctional Oxide Thin Films: A Review

“…They observed that the ion irradiation could drive the phase transition of BFO from rhombohedral (R) to C-type monoclinic (M C ), A-type monoclinic (M A ), and eventually tetragonal (T). Chen et al also observed a similar R-Mc-T-super-tetragonal (ST) phase transition in the epitaxial BFO films using He 2+ ion implantation with an energy of 8 keV and ion fluence ranging from 5 × 10 14 to 5 × 10 15 cm –2 . Particularly, the ST phase exhibited a giant c/a ratio approaching ∼1.3.…”

Emergent properties at oxide interfaces controlled by ferroelectric polarization

“…For the same reason, enhancing the polarization of ultrathin films has become very important. In general, strain engineering and defect engineering can be used to optimize the polarization properties 64,66,[196][197][198] . The introduction of freestanding films also opens the door for many avenues for polarization enhancement to be explored as the thin film can be transferred to any substrate 77 .…”