An investigation of the dielectric energy storage performance of Bi(Mg2/3Nb1/3)O3-modifed BaTiO3 Pb-free bulk ceramics with improved temperature/frequency stability

(BaTiO3–SrTiO3)/(WO3)x ceramics with x = 0 up to 5% were synthesized using solid-state reaction via high-energy ballf milling technique. Various characterization techniques were used including X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform-infrared spectroscopy (FT-IR), and UV–visible diffuse reflectance (DR) spectrophotometer. Structural analysis via XRD indicates the formation of two separate phases of SrTiO3 (STO) and BaTiO3 (BTO) having both cubic structures. The presence of BaWO4 as impurity was detected for higher concentration. SEM observations show a reduction in the average grains size with increasing WO3 addition. In comparison with free-added ceramic, the optical band gap energy (Eg) shows a slight increase with WO3 addition. Contextual investigations on the electrical and dielectric properties of various WO3 added to BTO–STO ceramics have been used to evaluate conductivity ($$\sigma$$), dielectric constant and loss ($$\varepsilon^{\prime}_{r}$$ and $$\varepsilon^{\prime\prime}_{r}$$), and dissipation factor ($$\mathrm{t}\mathrm{a}\mathrm{n}\delta$$) against both frequency and dc bias voltages. Generally, both $$\sigma$$ and $$\varepsilon^{\prime\prime}_{r}$$ correspond to the tendency of the power law to frequency. However, dc bias has been noticed to be lesser affecting the conduction mechanisms, which has a small variation for various WO3 addition ratios. In addition, the dissipation factor was found to be highly dependent on both the addition ratio and the frequency as well as dc bias applied.

Role of WO3 nanoparticles in electrical and dielectric properties of BaTiO3–SrTiO3 ceramics

Spintronics is a promising technology which aims to solve the major problems existing in today’s conventional electronic devices. Realistically, this technology has the ability to combine the main functions of the modern semiconductor microelectronics and magnetic storage devices in single chip. Electrons have two fundamental degrees of freedom (DOF) called charge and spin. Conventional electronic devices used only the charge of electron for information processing using binary bits 0 and 1. The continuous developments in the conventional electronics are basically depending on reducing component size (transistors, capacitors, etc.) embedded in integrated circuits (random access memory, microprocessor, etc.). In 2019, the actual size of the transistor placed in commercial microprocessor is about 50 nm with gate length of 20 nm and node of 7 nm fabricated using TSMC’s 7-nm FinFET (Taiwan Semiconductor Manufacturing Company 7-nm Fin Field Effect Transistor). The progress in the electronic devices will come to the end when the transistor node size reaches to 1 nm. Below this size, the fabrication, writing, and reading processes will be difficult or impossible due to quantum size effect. Spintronics is the alternative future technology, which is based on using the fundamental spin of electron in additions to its charge to carry and store information. Transfer from conventional electronics to spintronics technology opens the possibilities to construct devices with high storage density, low power consummation, and fast operation and that are cheap and robust. The main aim of this work is to give a simple and clear picture to researchers who are beginners of research in this field. In this review, basic outlines of spintronics technology and its fundamental properties were discussed. Here, we highlight two groups of materials strongly candidates to fabricate spintronics devices, denoted diluted magnetic semiconductor and multiferroic materials.

Spintronics: Future Technology for New Data Storage and Communication Devices

Effect of Al substitution on the structural, electric and impedance behavior of cobalt ferrite

Structural refinement, investigation of dielectric and magnetic properties of NBT doped BaFe12O19 novel composite system

Improved magnetoelectric effect in ytterbium doped BaTiO3 –CoFe2O4 particulate multiferroic composites

Magnetodielectric effect in rare earth doped BaTiO3-CoFe2O4 multiferroic composites

Magneto-dielectric studies on multiferroic composites of Pr doped CoFe2O4 and Yb doped PbZrTiO3

BaTiO3–BaFe12O19 composite was prepared by solid state reaction method. Ferroelectric barium titanate and ferrimagnetic barium hexaferrite phases were prepared separately. From morphological studies, the distribution of barium titanate and barium hexaferrite grains was confirmed. The evaluation of densities showed that the composite is denser compared to the individual phases. The polarization versus electric field experiment showed typical hysteresis loops, confirming the presence ferroelectric phase in the composite. Dielectric studies carried on the composite samples showed a diffused type of ferroelectric phase transition. Various magnetic parameters of the composite system were studied and compared to the barium hexaferrite phase. The first order reversal curve method was used to confirm the presence of single and multidomain structures in barium hexaferrite and the composite system.

Dielectric, ferroelectric and magnetic behavior of BaTiO3–BaFe12O19 composite

The present study focuses on the effects of rare-earth (R) ion substitutions namely Y, Sm and Pr ions on the structural, magnetic and electrical properties of cobalt ferrite (CFO) and the nature of their magnetic domains using the first-order reversal curve (FORC) analysis. These samples were synthesized using the sol–gel auto-combustion method. The powder X-ray diffraction analysis reveals that the Pr-substituted CFO crystallizes in a single-phase spinel structure, while a few traces of RFeO3 appear as minor phases in Sm- and Y-doped CFO. The scanning electron micrographs show that the substitution of R3+ ions causes a considerable reduction in the grain size. The studies on magnetic properties reveal that the saturation magnetization of R-substituted CFO decreased. The FORC analysis was done to know the domain state of magnetization and the nature of magnetic interactions among the grains. All the FORC diagrams depict a single peak with a single contour suggesting that all the synthesized samples have single domain particles and are comprised only of mono-magnetic phase. The electrical properties of the R-doped CFO compounds exhibit high values of dielectric constant at room temperature with the highest value for Pr-doped CFO. The activation energy determined using electrical properties is found to decrease with R doping.

Mehraj ud Din Rather

Papers

Improved magnetoelectric effect in ytterbium doped BaTiO3 –CoFe2O4 particulate multiferroic composites

Magnetodielectric effect in rare earth doped BaTiO3-CoFe2O4 multiferroic composites

Magneto-dielectric studies on multiferroic composites of Pr doped CoFe2O4 and Yb doped PbZrTiO3

Dielectric, ferroelectric and magnetic behavior of BaTiO3–BaFe12O19 composite

Dielectric and magnetic properties of rare-earth-doped cobalt ferrites and their first-order reversal curve analysis