Browsing by Author "Verma, Ramesh"

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    Low Loss Soft Ferrites Nanoparticles for Applications Up to S-band
    (Springer Science and Business Media Deutschland GmbH, 2021-10-29T00:00:00) Sharma, Sucheta; Verma, Ramesh; Singh, Mahavir; Sharma, Surender K.
    This chapter aims at providing a better understanding of soft ferrites and their role in ultra-high-frequency applications. In wireless communication industry trends of miniaturized, highly efficient and wide-band antenna become the new research areas of the antenna technology. Antenna miniaturization cannot be achieved by simply changing the structural design, and it is important to improve the material characteristics of antenna substrates. Furthermore, to improve the antenna efficiency, almost matched permittivity and permeability values and low magnetic as well as dielectric loss tangents are required especially at ultra-high frequency (UHF), L-band, and S-band frequency range. For efficiency improvement and miniaturization of antennas, magneto-dielectric materials have significant advantages with matching permittivity and permeability values along with sufficiently low magnetic and dielectric loss tangents. Ferrites with very high resistance have been reported as the best host materials to produce low loss magneto-dielectric materials for high-frequency antenna applications as they present moderate permeability and permittivity values. In this chapter, the emphasis is given on the soft ferrites Mn�Zn, Ni�Zn spinel ferrite, and Co2Z type barium hexaferrite. The chapter also explains the effect of substitution of different dopant ions on the properties of soft ferrites. � 2021, Springer Nature Switzerland AG.
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    Superparamagnetic Iron Oxide-Based Nanomaterials for Magnetic Resonance Imaging
    (Springer Science and Business Media Deutschland GmbH, 2021-10-29T00:00:00) Niraula, Gopal; Mathpal, Mohan Chandra; Medrano, Jason J. A.; Singh, Manish Kumar; Coaquira, Jose A. H.; Verma, Ramesh; Sharma, Surender K.
    Magnetic resonance imaging (MRI) is the technique for the visualization of targeted macromolecules or cells in biological system. Nowadays, superparamagnetic iron oxide nanoparticles (SPIONs) have been attracted and remarkably emerging as a negative contrast agent (T2-weighted) offering sufficient detection sensitivity as compared to positive contrast agent (T1-weighted). In the present chapter, we first introduce the necessary background of superparamagnetic iron oxide-based nanoparticles and MRI taking into an account to discuss both T1�T2-weighted imaging. The liquid-based synthesis methods of SPIONs and their applicability in MRI have been thoroughly revised. Finally, several nanohybrids such as magnetic-silica, magneto-luminescent, magneto-plasmonic along with ferrite-based SPIONs are thoroughly presented in light of MRI application. � 2021, Springer Nature Switzerland AG.