Narrow Results

A series of Bi${}_{0.8}$Ba${}_{0.2}$Fe${}_{1-x}$Co_xO₃ ($x=0.00$, 0.05, 0.10, and 0.15) samples were synthesized using the tartaric acid modified sol–gel method. The crystal structure of the prepared samples was analyzed by XRD, and the samples co-doped with Ba and Co were all rhombohedral distorted structures with the R3c space group. With an increase in the doping amount, a reduction in lattice parameters was observed along with crystallite sizes consistently being below 62nm. Mössbauer spectral analysis at room temperature reveals a good fit with two sextets and a doublet, all attributed to the Fe${}^{3+}$ state. This suggests that the charge balance within the samples is maintained through the generation of oxygen vacancies in the system. The hysteresis loops of all samples revealed the weak ferromagnetic of the Co-doped Bi${}_{0.8}$Ba${}_{0.2}$FeO₃ nanoparticles. With the increase in Co doping, the magnetic parameters such as saturation magnetization and coercive field significantly improved.

We have fabricated BiFeO₃ thin film deposited on Pt/Ti/SiO2/Si substrates by the chemical solution deposition method. The effects of annealing temperature on the thin film structure, resistance switching (RS) properties, conduction mechanisms are investigated. It exhibits improved RS window with high ON/OFF ratio ($\sim$10⁴) for the sample annealed at 650${}^{\circ }$C. XPS characterization indicates that cation ratio of Fe${}^{2+}$/Fe${}^{3+}$ is increased with increasing annealing temperature. Crystal lattice distortion generated by Fe${}^{2+}$ cations, along with oxygen vacancies, commonly contribute to opening the RS window and the increment of conductive filaments. The film’s conduction mechanisms under different annealing temperatures are fully discussed. The RS properties of this system can be effectively improved by increasing the annealing temperature, which is crucial prerequisite for future applications of BFO-based thin film device in resistance random access memory.

Neodymium and manganese-doped BiFeO₃ — (Bi_0.95Nd_0.05)(Fe_0.95Mn_0.05)O₃(BNFMO) ferroelectric film and HfO₂ layer with different thickness were fabricated using metal-organic decomposition and atomic layer deposition (ALD) method, respectively. Metal-ferroelectric-insulator-semiconductor (MFIS) capacitors with 200 nm thick BNFMO and 5 nm thick HfO₂ layer on silicon substrate have been prepared and characterized. It is found that there is no distinct interdiffusion and reaction occurring at the interface between BNFMO/HfO₂ and HfO₂/Si. The capacitance–voltage (C–V) and leakage current properties of Pt/HfO₂/Si capacitors with different HfO₂ thickness were studied. The MFIS structure showed clockwise C–V hysteresis loops due to the ferroelectric polarization of BNFMO. The maximum memory window is 5 V. The leakage current of the Pt/BNFMO/HfO₂/Si capacitor was about 2.1 × 10^-6 A/cm² at an applied voltage of 4 V.

Bismuth ferrite (BFO) nanostructures and thin films have gained attraction as suitable candidates for energy storage and energy conversion due to their high energy storage efficiency, temperature stability and low dielectric loss. Electrical properties of such multiferroic materials are tailored by ferroelectric and ferromagnetic constituents and have opened up amazing avenues in electrochemical supercapacitor and photovoltaic applications. Dopants play a significant role in optimizing the magnetic and dielectric properties of such materials owing to suitable applications. This review highlights the scientific advancements reported in BFO nanostructures for energy applications by optimizing their magnetic and dielectric properties. This paper starts with a brief introduction of BFO and a discussion on the effects of various dopants by different synthesis techniques, and their effects on the magnetic and dielectric properties are also portrayed. Eventually, this review summarizes the various doping effects, which paves way for future research on this multiferroic material.