Engineered Ferrites and Their Applications

Special magnetic materials called ferrites have both magnetic and electric characteristics. As a result, it is crucial from both a commercial and scientific standpoint to research them for usage in applications such as energy storage devices, chip ferrite markets, household appliances, communication, and electronics. Chemists, physicists, and materials scientists must work together to examine both fundamental qualities and prospective applications in order to understand the relationship between the structure, magnetic properties, and applications. In accordance with the process causing the magnetic characteristics, this chapter offers categorization of ferrites relying on cation occupancy and magnetic field. In order to comprehend structural arrangement better, the key magnetic properties of concern and the conceptual approaches developed to explain these features are outlined.

Ferrites with compositional expression as X. Fe₂O₄ where X is any dopant (mono, divalent and trivalent ion) are a class of materials which are semiconductors in nature and can also be easily magnetized, acquiring excellent electrical and magnetic properties. Ferrites comprise iron oxide (Fe₂O₃) in combination with chemically balanced dopants and possess high chemical stability, high Curie temperature, tunable shape and particle size. Ferrites are mainly categorized into soft, hard and mixed ferrites, and due to their superior properties, they can be used as inductors, transformers, electronic absorbers, sensors, etc. The application can also be extended to biomedical, waste water management and in catalysis, etc. Applications are mainly dependent on properties which are tailored to match the operational aspects of ferrites, and this further depends on the dopants used while synthesis. The dopants are selected based on the valency, ionic size, crystal structure, melting point, and magnetic moment and upon doping optimize magnetic and electrical properties. Along with the nature of dopants, the structural properties such as density, Curie temperature and porosity can be modified by selecting different synthesis routes and sintering techniques/conditions.

Preparation of ultrafine nanoparticles has attracted the vast attention of researchers due to their wide scopes in numerous areas. Ferrites are widely used in scientific and technological applications such as permanent magnet, magnetic fluids, electromagnetic absorbing materials, LED, printer, transducers, and storage capacity. Ferrites have high resistivity, coercivity, saturation magnetization, and permeability. The unique behavior and characteristics make these materials useful in other applications in which ferrites are preferentially used in biomedical field for the treatment of hyperthermia, cancer as well as drug delivery agents. These properties are sturdily dependent upon the electronic configuration and crystallographic site preference of dopant. To obtain desired physical properties for various applications, cationic substitution has been preferred, i.e., substitution for Sr ions or Fe ions in crystallographic sites. In order to achieve the substitution of dopant ions at specific site, the several methods have been developed. Thus, efforts have been made to explore these methods of preparation including their pros and cons which helps to understand the mechanism, processing, and selection of ferrites for different applications in electronic industry, high-frequency devices, and biotechnology based upon their characteristics.

“No water, no life. No blue, no green.”—Sylvia Earle.

Despite 75% of aqueous flora fauna, humans are still struggling with potable water. In this regard, research groups have discovered various methodologies to recycle the used water. Among these approaches, advanced oxidation process (AOP) gained significant attention of researchers. More specifically, photocatalytic oxidation of organic pollutants (dyes, pigments, pesticides, etc.) seems simple and quick with non-toxic by-products. Here, semiconducting metal nanoparticles, metal oxides, and other chemical compounds have been exploited as photocatalysts due to inclined structural and optical properties. While the effect of magnetic features of such catalysts has not been studied much, here, magnetic field-directed electron spin may also affect the electron transfer in multi-component catalyst system. Moreover, the effect of external magnetic field and catalyst’s magnetic domains might also alter the electronic pathway for interfacial charge transfer phenomenon during illumination. Further, different morphological features can also be introduced to optimize the objective of development of an efficient and reusable photocatalyst with easier separation from solution.

A large category of magnetic nanoparticles (MNPs) includes ferrite nanoparticles (FNPs) which are employed extensively in biomedicine because of their suitability in living body, particularly in the treatment of hyperthermia. Nanoparticles made of ferrites are commonly employed in hot environments. Additionally, there are a number of requirements placed on nanoferrites by their use in hyperthermia therapies, including biocompatibility, less noxious, a definite amalgamation rate, small interval and amount inside the organic region to accomplish a predetermined hyperthermia temperature, and a minor “nanoferrite” dose. The effectiveness of nanoferrite materials in hyperthermia treatments is evaluated through research. As a result, this book chapter examines the benefits and drawbacks of ferrite nanoparticles in the treatment of hyperthermia, as well as enhanced ferrite-based nanocomposites to increase their effectiveness within biological molecules, which could be an encouraging future therapeutic agent for this disorder.

Ferrite nanoparticles have invited enormous scientific attraction because of their unique properties and up-and-coming applications. The ferrites are used in filter circuits and core materials for transformers. In turn is designed for broadband spectrum and antenna material in the telecommunication industry, like radio, television, mobile communication, etc. Eddy current losses are minimal at high frequencies because of ferrites’ significantly high resistance; therefore, a variety of applications can be exploited at extremely high frequencies, unlike other magnetic components. For a variety of applications, different material properties are desired. Therefore, ferrites materials having different compositions are used. To prevent electromagnetic interference, ferrite cores are employed to block low-frequency noise and absorb high-frequency noise. Spinel ferrites are used in transformer cores, microwave devices, and high-frequency devices in the electronics sector. If their dielectric loss is low, ferrite nanoparticles can be used in switching inductors, antenna rods, and microwave devices. Ferrites are an excellent option for both traditional and contemporary applications owing to their variety of shapes, ongoing breakthroughs in material characteristics and cost-effectiveness. In this chapter, the properties of ferrite nanoparticles are discussed, which play an essential role in making ferrite usable in the telecommunication industry, e.g., elastic properties, such as hysteresis, coercivity, and magnetic saturation. The usages of ferrites in various components of telecommunication equipments are also discussed, including filter circuits, broadband and core of transformers.

Rising prices of energy harvesting sources have badly affected the economy of the world. In present time energy harvesting has become a major challenge for scientists. Scientists from all over the world are trying to create such a material which largely reduces the cost of energy production. The composition as well as microstructure of materials used to develop component of these sources has large impact on their performance. Physical and chemical properties of the material depend on their synthesis root. Large number of the materials has been studied to develop these sources till date and multi-ferities are one of them. Multiferroic materials are also used to develop the components for various types of energy sources. Structural, electrical, optical, thermal, and magnetic properties of multi-ferities are greatly affected by its process of synthesis as well as doping of different metals or other elements in it. In this chapter different type of energy harvesting sources along with multi-ferities material used in developing their components has been presented. Finally, this review has been concluded with several perspectives on the future of research directions in this area.

Electromagnetic pollution is among the biggest environmental issues. The utilization of electrical and electronic appliances is expanding quickly, which also increases the production of electromagnetic wave over the same frequency spectrum by another piece of equipment. In the modern era, EMI has grown to be a significant issue. EMI is the term used to describe a decline in a system’s or device’s performance brought on by the unpredicted conductance of impulses from some of the other electrical devices. Due to the versatility, non-corrosiveness, light weight, and ease of production, hybrid nanoferrite-polymer composites are employed in a variety of applications including EMI shielding particularly in the field of digital electronics and communication. This chapter involves the literature of different ferrite nanocomposite materials for electromagnetic shielding applications.

Ferrite is a metal oxide with the formula XFe₂O₄, where X is a divalent metal such as Fe, Ni, Co, Cu, or Mg. Ferrite nanoparticles (FNPs) have undergone several studies to find their electrical and magnetic properties and to exploit them for nanotechnological applications. In recent years, FNPs and composites have received considerable interest because of their applications in various sensing. Due to the abundance of literature on synthesis methods, we will focus exclusively on the widespread application of FNPs in sensor systems. In this chapter, we will discuss the different sensor systems and recent developments. The classification of sensors according to their underlying sensing processes is not currently explained in any review work. In this chapter, we start with an overview of FNPs. This is followed by a discussion of the various sensing principles, including electrochemical, optical, piezoelectric, and magnetic, including their application in gas sensors, biosensors, chemical sensors, temperature sensors, stress sensors, and giant magnetoresistance sensors. In addition, we will discuss the role of FNPs in the development of biochemical sensors based on SERS. At the end, we will discuss the difficulties, prospects, and our conclusions.

Clean and green energy is need of today’s era to overcome the environmental pollution caused by combustion of fossil fuels. Generation and conservation of energy is a great concern in meeting such targets of preventing environmental pollution and satisfying the increasing energy demand. A variety of energy storage devices like supercapacitors, fuel cells and rechargeable batteries have gained attention to solve the purpose of energy storage with high efficiency. Among these energy storage devices, supercapacitors are the most widely studied by scientists worldwide owing to their high power and current density, long-time cycling stability and fast charge/discharge rates. The supercapacitors can be used specifically as back-up power devices. However, the main shortcoming with a supercapacitor is its low energy density which hinders its applications for practical purposes and thus poses a great challenge in exploring them for high energy and power density. This chapter discusses the role of ferrite nanostructures as efficient materials for energy storage devices. In case of ferrites, there are fast and reversible redox reactions occurring at the interface of electrode/electrolyte which give rise to charge storage. To design a promising and highly efficient supercapacitor, the electrode material must have following properties: high specific capacitance, low cost for synthesis, wide range of operating potential and easy availability on earth. Specifically, ferrites having mixed oxidation states have proved themselves as desirable candidates for designing electrodes in supercapacitors. This chapter will discuss the ferrite nanostructures and their electrochemical properties for applications in energy storage devices.

The concept with distinctive, significantly altered physical, chemical, or biological characteristics of materials may be acquired when their size is shrunk to nanometer dimensions is the driving force behind current research in the manufacture of nano-sized materials. Recent reports state that various ferrites’ nanoparticles (Ferrite NPs) have antibacterial properties more effective than antibiotic medicines at combating human infections aside from silver nanoparticles’ (NPs) which is well-known antimicrobial agent. In general, there has been much emphasis on the assessment of magnetic nanoparticles for bio-medical and sensing applications. However, there is not much information available on the usage of ferrite nanoparticles as antimicrobials against pathogenic and drug-resistant microorganisms. The current chapter's goal is to describe the antimicrobial activity of ferrite nanoparticles against a variety of pathogenic microbes and also to describe their cytotoxic impact on cells.

Technological, social, and economic gains have all been seen in the twenty-first century. On the one hand, these innovations have raised the quality of life, but they have also brought about certain negative effects. Iron and steel industry has although provided a strong backbone for the industrialization, but pristine iron-based structures are prone to continuous degradation due to various factors. Corrosion is one of the most detrimental effect on metallic surface. Corrosion degrade the physical chemical characteristics of the material and leads to major defects in the machineries which further become the main reason for many accidents/tragedies. Primary solution for this includes various electrochemical and chemical treatments, coating for the exposed metallic surfaces, but these solutions are also of short duration. Through the development of sophisticated nanomaterials, nanotechnology has emerged as a leading light for several difficulties in recent years. Nanotechnology opens up numerous possibilities for creating technologies that are more useful, economical, and environmentally friendly than those that are already available in a variety of industries. Increased surface area, enhanced chemical reactivity, and mobility define nanoscale materials are among their key features. Some nanoparticles are employed as additives for surface coatings as well as for different metallic treatments because of their improved reactivity and suitably small size. Metallic nanoparticles, including Ag, Au, Zn, and metal oxide nanoparticles, have been widely exploited for their anticorrosion characteristics and as a key reinforcing element in coatings and paint compositions. Ferrite nanoparticles are new nanodimension materials with superparamagnetic behaviour and high surface-to-volume ratio. In recent years, the possible anticorrosion behaviour of ferrite-based nanoparticles has also been the main focus of study by different researchers. Nanoparticles have the potential to be anticorrosion through multifaceted mechanisms. The main topics covered in this chapter include the various types of ferrite nanoparticles with anticorrosion behaviour, anticorrosion mechanisms adopted by nanoferrites, factors influencing corrosion, and potential applications of such ferrite-based nanoparticles.

Ferrites have attracted a lot of attention in the last decade because of their numerous applications, particularly in the biomedical field where their improved magnetic characteristics are helpful for a variety of imaging, medical diagnosis, and available therapies. Ferrites’ strong magnetic properties make them potential nanoagents for a number of applications, such as magnetic separation, targeted drug delivery, biosensors, MRI, nanorobots, and magnetic hyperthermia (MHT). In biomedical applications, nanoferrites’ efficacy is influenced by their shape, chemical, and physical characteristics, and biocompatibility. In this chapter, an attempt is made to inform readers about various required characteristics as well as the most recent implementations of these traits that have been used effectively in the commercialized biomedical field. Additionally, we'll discuss current developments in engineered magnetic ferrite nanoparticles (MFNPs) for biomedical uses.