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In the present review paper, we have explained the structure of Y-type hexagonal ferrite and various synthesis techniques. This paper also includes structural, electrical, magnetic properties and applications of Y-type hexaferrites and focusses on their use in antenna applications and microwave absorbing characteristic materials. Ferromagnetic nature of hexaferrites cause the induction of magnetisation within the crystal structure, which divide them into two groups: First with easy axis of magnetisation is known as uniaxial hexaferrites and second is known as ferroxplana having easy plane of magnetisation. The excellent magnetic properties of Y-type ferrites make them useful in the devices operating at high frequency range. The persistence of high refractive index upto 1 GHz enables these hexagonal ferrites useful in UHF antenna designs with small dimensions. The doping in Y-type hexaferrites affect all the properties. Current developments in Y-type hexaferrites will be explained in detail in the review of literature related to Y-type hexaferrites for the last 25 years, i.e. from 1994 to 2019 in this review paper.

Precise studies of cadmium and indium doped barium hexagonal ferrites having chemical composition Ba0.7Nd0.3Cdx/2Inx/2Fe12-xO19 (x = 0.0, 0.1, 0.2, 0.3) have been performed by sol-gel auto-combustion method in which ethylene glycol was used as a gel precursor. The structural, morphological, optical, elemental and magnetic properties have been studied by using various techniques like XRD, FESEM, FTIR, EDS and VSM. The XRD patterns shows characteristic (110), (008), (107), (114), (108), (203), (205), (206), (1011), (300), (217), (2011), (220), (2014) peaks along with the presence of secondary phase confirming the formation of hexagonal structure with an average crystallite size of 43–59 nm. FESEM supports the formation of hexagonal, dense and agglomerated nanoparticles. The Vibronic study using infrared radiation was carried by FTIR analysis reveal the various configuration modes with hexagonal symmetry of prepared nanoparticles. The magnetic measurements have been studied at room temperature indicates that saturation magnetization (Ms) and magnetic moment (nB) found to be of range 40–86 emu/g and 7.97–17.23 μB. The precise magnetic studies made it possible to reveal that saturation magnetization (Ms) increases with the cadmium and indium concentration for x = 0.1 and after that it decreases for x = 0.2, 0.3 which may be due to the difference in the magnetic moments of Cd, In and Fe ions. Due to high value of saturation magnetization (Ms), it can be used for applications in the field of high density recording storage devices and also, this magnetic change has been explained on the basis of exchange interactions. The room temperature Mo¨ssbauer spectra of all the nano-sized materials shows normal Zeeman splitting consisting of six merged line patterns which indicates the formation of ferromagnetic phase that supports the magnetic properties. Keywords: Barium neodymium nanoparticles, Sol-gel, Structural and optical analysis, Magnetic measurements, Mo¨ssbauer spectra

Nano-sized magnetic particles of Yttrium, Samarium, and Dysprosium doped Nickel Cobalt Zinc were successfully synthesized by the sol-gel auto-combustion technique in order to investigate different structural, morphological, elemental, optical and magnetic properties with the usage of different characterization techniques. The characterization techniques used for studying different properties of synthesized samples were XRD, FESEM, EDS, FTIR, and VSM. The XRD patterns revealed the formation of single-phase inverse spinel cubic structure with an average crystallite size (D) in the range of 59–63 nm. The surface morphology of the synthesized samples carried out by FESEM surely indicates the formation of dense, cubic in shape and agglomerated magnetic nanoparticles. The EDS spectra of prepared samples show the formation of pure magnetic nanoparticles. The Fourier infrared transform spectroscopy supports our XRD results to a great extent that the synthesized magnetic nanoparticles have single-phase inverse spinel cubic structure by giving the spectrum in the range of 419–594 cm−1. The magnetic measurements were carried out by Vibrating Sample Magnetometer for calculating different magnetic parameters such as saturation magnetization (Ms), coercivity (Hc), remanent magnetization (Hc) and magnetic moment (nB) which was found to be in the range of 54–63 emu/g, 34–209 Oe, 1.99–19.89 emu/g and 2.29–2.66. The magnetic analysis of synthesized samples has been explained on the basis of the theory of exchange interactions and Neel's sublattice model. Keywords: NiCoZn magnetic nanoparticles, Structural study, FESEM, FTIR spectra, Magnetic measurements