Magnetics, Dielectrics, and Wave Propagation with MATLAB® Codes

2023-09-13 · 5 citations

Future microwave, wireless communication systems, computer chip designs, and sensor systems will require miniature fabrication processes in the order of nanometers or less as well as the fusion of various material technologies to produce composites consisting of many different materials. This requires distinctly multidisciplinary collaborations, implying that specialized approaches will not be able to address future world markets in communication, computer, and electronic miniaturized products. Anticipating that many students lack specialized simultaneous training in magnetism and magnetics, as well as in other material technologies, Magnetics, Dielectrics, and Wave Propagation with MATLABR Codes avoids application-specific descriptions, opting for a general point of view of materials per se. Specifically, this book develops a general theory to show how a magnetic system of spins is coupled to acoustic motions, magnetoelectric systems, and superconductors. Phenomenological approaches are connected to atomic-scale formulations that reduce complex calculations to essential forms and address basic interactions at any scale of dimensionalities. With simple and clear coverage of everything from first principles to calculation tools, the book revisits fundamentals that govern magnetic, acoustic, superconducting, and magnetoelectric motions at the atomic and macroscopic scales, including superlattices. Constitutive equations in Maxwell’s equations are introduced via general free energy expressions which include magnetic parameters as well as acoustic, magnetoelectric, semiconductor, and superconducting parameters derived from first principles. More importantly, this book facilitates the derivation of these parameters, as the dimensionality of materials is reduced toward the microscopic scale, thus introducing new concepts. The deposition of ferrite films at the atomic scale complements the approach toward the understanding of the physics of miniaturized composites. Thus, a systematic formalism of deriving the permeability or the magnetoelectric coupling tensors from first principles, rather than from an ad hoc approach, bridges the gap between microscopic and macroscopic principles as applied to wave propagation and other applications.

Synthesis and Characterization of High-Purity Yttrium-Iron-Garnet Nanowires Inside a Porous Silicon Membrane by the Sol–Gel Method

IEEE Magnetics Letters · 2020-01-01 · 5 citations

Recently, nonmetallic ferromagnetic nanowires (NWs) have been implemented in porous templates. Such composite substrates are used to design various microwave, magnetic, and electronic devices. To synthesize ferrite NWs, the precursor solution consists of either magnetic nanoparticles (NPs) dispersed in a polymer as a surfactant or metal nitrates, which are used in a sol-gel method. The magnetic properties of ferrite NPs change significantly due to their large surface-to-volume ratio. For these NPs, the saturation magnetization is reduced due to the superparamagnetism phenomenon. In this letter, we investigated the increase of the saturation magnetization and the volume loading of synthesized yttrium iron garnet (YIG) NWs in a porous silicon membrane. To enhance the filling factor of the YIG NWs, multiple techniques are utilized, such as a permanent magnet, bath sonication, and vacuum suction. Our experiments show that in the sol-gel method using vacuum suction, the NWs loading factor can be greater than a 50%, as the purity of the YIG NWs increases to 98.2% by decreasing the precursor molarity (from 2 to 1 M), reducing the oxygen flow in the electric furnace (from 10-20 standard liters per minute to 5-10 SLPM) and increasing the magnetic stirring time (up to 24 h). The magnetic properties of the YIG NWs are investigated using a vibrating sample magnetometer.