Structural and Ferroelectric Properties of Domain-Structure-Controlled BiFeO₃ Thin Films Prepared by Dual-Ion-Beam Sputtering

Abstract

BiFeO3 (BFO) thin films have been grown on vicinal SrTiO3 (STO) (001) substrates by dual-ion-beam sputtering. The Bi/Fe composition ratio was optimized by adjusting the beam current ratio of a dual-ion beam. The domain structure was controlled using a vicinal STO substrate along <100> and <110>. From the results of X-ray diffraction analysis and piezoelectric force microscopy, it is found that BFO thin films grown on vicinal STO along <100> and <110> show stripe and single-domain structures, respectively. It is found that the reduction in the length of non-180° domain walls improves leakage current characteristics, resulting in an enhancement of ferroelectric D–E characteristics. The single-domain BFO thin film shows excellent D–E hysteresis loops at room temperature, with a double remanent polarization (2P r) and a double coercive field (2E c) of 140 µC/cm2 and 340 kV/cm, respectively.

Influence of Lattice Distortion Induced by a Vicinal SrTiO3(001) Substrate in Single-Domain BiFeO3 Thin Films Prepared by Radio Frequency Planar Magnetron Sputtering

“…2) However, 2P r and 2E c are slightly smaller than those of single-domain BFO film prepared by dual ion beam sputtering of 140 C/cm 2 and 340 kV/cm. 34) The differences might be due to domain cramping caused by plasma induced damage or interface traps induced by Fe 2þ / Fe 3þ fluctuation. To clarify the reason, a more detailed investigation is necessary.…”

“…31) We have also reported the domain structure control and high-quality thin-film preparation of BFO films by dual ion beam sputtering. [32][33][34] However, the details of the properties of the single-domain BFO films including the epitaxial strain effect have not been investigated yet. On the other hand, the major deposition processes for BFO thin films are pulsed laser deposition 1,10) and chemical solution deposition.…”

Enhancement of photovoltage by electronic structure evolution in multiferroic Mn-doped BiFeO3 thin films

“…Therefore, 1 µm thick BFMO thin films with various amounts of dopant (0, 0.5, 1.0, 3.0 and 10 at%) were grown on vicinal SrTiO 3 (001) (STO) substrates by conventional RF planar magnetron sputtering process. Vicinal STO substrates with the [001] STO direction inclined 4° toward [110] STO have been used for the domain engineering [25][26][27][28] of BFMO thin films. Figure 1a-c show surface atomic force microscopy (AFM), and vertical and lateral piezoresponse force microscopy (PFM) images of a Mn 1 at%-doped BFO thin film.…”

Sprayed tungsten-doped and undoped bismuth ferrite nanostructured films for reducing and oxidizing gas sensor applications

“…Several deposition methods have been envisaged to grow BFO films/powders. Physical deposition methods, such as solid-state [25,26], pulsed laser deposition [27][28][29], molecular beam epi-taxy [30] and sputtering [31,32], sol-gel, [33,34], co-precipitation [35,36] and hydrothermal methods [37,38] have been applied to the synthesis of BFO films with various morphologies. In addition, there are few reports on the doping and applications of other elements with BFO [39][40][41] where researchers are optimistic about improv-ing the physical and chemical properties of BFO by substitutional doping with various elements to modify electronic properties.…”