Synthesis and Characterization of Multiferroic BiFeO3 for Data Storage

Multiferroic BiFeO3 deals with spintronic devices involved spin-charge processes and applicable in new non-volatile memory devices to store information for computing performance and the magnetic random access memories storage. Since multiferroic leads to the new generation memory devices for which the data can be written electrically and read magnetically. The main advantage of present study of multiferroic BiFeO3 is that to observe magnetoelectric effects at room temperature. The nanostructural growth (for both size and shape) of BiFeO3 may depend on the selection of appropriate synthesis route, reaction conditions and heating processes. In pure BiFeO3, the ferroelectricity is induced by 6s2 lone-pair electrons of Bi3+ ions and the G-type antiferromagnetic ordering resulting from Fe3+ spins order of cycloidal (62-64 nm wavelength) occurred below Neel temperature, TN = 640 K. The multiferroicity of BiFeO3 is disappeared due to factors such as impurity phases, leakage current and low value of magnetization. Therefore, to overcome such factors to get multiferroic enhancement in BiFeO3, there are different possible ways like changes dopant ions and their concentrations, BiFeO3 composites as well as thin films especially multilayers.

Radiation Effect on Optical Properties of Bi-Related Materials Co-Doped Silica Optical Fibers

Three kinds of Bi-related materials co-doped silica optical fibers (BRDFs), including Bi/Al, Bi/Pb, and Bi/Er co-doped fibers, were fabricated using atomic layer deposition (ALD) and modified chemical vapor deposition (MCVD). Then, the effect of irradiation on the optical properties of BRDFs was investigated. The experimental results showed that the fluorescence intensity, the fluorescence lifetime of BRDFs at the 1150 nm band, increased significantly with low-dose treatment, whereas it decreased with a further increase in the radiation dose. In addition, the merit Mα values of the BRDFs, a ratio of useful pump absorption to total pump absorption, decreased with an increase of the radiation doses. The Verdet constants of different doped fibers increased up to saturation level with increases in the radiation dose. However, for a Bi-doped fiber, its Verdet constant decreased and the direction of Faraday’s rotation changed under low-dose radiation treatment. In addition, the Verdet constant increase of the Bi-doped silica fiber was much faster than that of other single mode fiber (SMF) and Pb-doped silica fibers treated with high-dose radiation. All of these findings are of great significance for the study of the optical properties of BRDFs.

BAC Photobleaching in Bismuth-Doped and Bismuth/Erbium Co-Doped Optical Fibers

Bismuth-doped optical fiber (BDF) and bismuth/erbium co-doped optical fiber (BEDF) have attracted much attention due to their ultra-broadband luminescence in the near-infrared (NIR) region. The photobleaching effect on bismuth active centers (BACs) related to the NIR luminescence has been systematically investigated and summarized, in terms of irradiation intensity, irradiation wavelength, and temperature. All these findings not only give the deep insights into the fundamental structure of BACs but also provide an effective way to control the BACs. They play an important role for the development of BDF- and BEDF-based devices with high performance and stability under laser exposure in future.

Effects of Electron Irradiation on Optical Properties of Bismuth-Doped Phosphosilicate Fiber

The basic optical properties of yttrium-phosphosilicate fiber doped with bismuth (Bi) are assessed in both pristine state and that established after bombardment by a beam of high-energy electrons. The fiber has been developed and fabricated with a target to use it for laser applications in visible/near-infrared (VIS/NIR) domain. In this chapter, the main attention is paid to the dramatic changes in absorption spectra of the fiber under electron irradiation. Meanwhile, we reveal its overall resistance to irradiation in terms of emissive potential and bleaching contrast at excitation into the absorption bands of bismuth-related active centers. Besides, we report a new effect of large dose-dependent Stokes shift, experienced by the fiber’s cutoff wavelength, which arises due to refractive index rise in its core area. The laws obeyed by the fiber’s characteristics vs. dose are examined for possible applications in dosimetry.

Development of Bismuth-Doped Fibers (BDFs) in Optical Communication Systems

This chapter will provide background information in the development of BDFs and their applications in optical communication systems. Herein, the main focus is briefly described previous studies on BDFs that have attracted much interest over the last two decades. This necessary information and concepts are very much relevant to understanding this book, mainly due to the doping of Bi in the studied bismuth and erbium-doped silicate fibers (BEDFs). The remaining chapter is consisting of the following sections: Sec.2: General introduction about optical fibers. Sec. 3 discusses the general spectral characteristics of BDFs. Sec.4: Including the active centers (namely the bismuth (Bi) active centers (BACs)) responsible for the spectral properties in Bi-doped fibers. Sec.4 Discusses the Bismuth Doped Fiber Amplifier (BDFA).

Investigation of Structural, Microstructural, Dielectrical and Magnetic Properties of Bi3+ Doped Manganese Spinel Ferrite Nanoparticles for Photonic Applications

The structural, microstructural, and magnetic properties of Mn1-xBixFe2O4 (where x = 0.0, 0.05, 0.1, 0.15, and 0.2) nanoparticles prepared by solution combustion method were investigated. Rietveld-refined X-ray diffraction patterns confirm the single-phase formation with space group Fd3m having spinel cubic structure. The porous nature of the samples was confirmed by scanning electron microscopy (SEM). Composition values of the theoretical stoichiometry and energy-dispersive spectroscopy (EDS) composition values are well matched for all samples. The dielectric parameters such as real part of dielectric constant, imaginary part of dielectric constant, and dielectric loss tangent decrease with the increase in frequency. The AC conductivity increases with increase in the Bi3+ concentration. The real part of complex impedance decreases with the increase in frequency. Cole-Cole plots reveal that one semicircle was obtained for each of the samples. The real and imaginary parts of electric modulus vary with frequency. The magnetic hysteresis curves of all samples reveal the soft magnetic material nature. We observed S esteems began uniquely from the higher superparamagnetic, we would have watched the monotonic decrease in S with increase in Bi3+ concentration. Furthermore, the magnetic parameters were estimated.

Bismuth Halide Perovskites for Photovoltaic Applications

In the last decade, energy crisis has become the most important topic for researchers. Energy requirements have increased drastically. To overcome the issue of energy crisis in near future, numerous efforts and sources have been developed. Therefore, solar energy has been considered the most promising energy source compared to other energy sources. There were different kinds of photovoltaic devices developed, but perovskite solar cells have been considered the most efficient and promising solar cell. The perovskite solar cells were invented in 2009 and crossed an excellent power conversion efficiency of 25%. However, it has a few major drawbacks, such as the presence of highly toxic lead (Pb) and poor stability. Hence, numerous efforts were made toward the replacement of Pb and highly stable perovskite solar cells in the last few years. Bismuth halide perovskite solar cell is one type of the replacement introduced to overcome these issues. In this chapter, I have reviewed the role of bismuth halide perovskite structures and their optoelectronic properties toward the development of perovskite solar cells.