Structural, Magnetic and Microwave Properties of Eu-doped Barium Hexaferrite Powders

Abstract

Eu-doped M-type barium ferrite powders (Ba 1−x Eu x Fe 12 O 19 ) with x = 0.0, 0.1, 0.2 and 0.25 were prepared by sol-gel method. The synthesized samples are characterized by thermo gravimetric analysis (TG-DTA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and vector network analyzer. All the synthesized samples have the nearly singlemagnetoplumbite phase. The results show that the crystallite size of doped samples is smaller than pure one. The saturation magnetization of doped ferrites decreases by the increase in Eu doping, while the coercivity increases. Maximum coercivity achieved in this study is 6.12 KOe for x = 0.25 sample. The enhancement of coercivity by Eu doping is mainly due to the higher magnetocrystalline anisotropy, which is attributed to the partial change of Fe +3 ion to Fe +2 ion. The maximum reflection loss (RL) of −43 dB at frequency range of 12-18 GHz for the x = 0.1 sample was obtained. The increase in reflection loss at higher frequency suggests that the Eu-doped sample can be used for the application in microwave devices.

Structural, Magnetic, and Microwave-Absorption Properties of Nanocrystalline Ca(MnSn) x Fe12−2x O19 Ferrites

“…XRD data were used to calculate cell constants, crystallite sizes (D), and cell volume (V), by use of equations reported elsewhere. 21,22 The lattice/cell constants a and c were calculated by solving the simultaneous equations for different diffraction peaks, by using the equation…”

Microstructural Characteristics and Magnetic Properties of Al-Substituted Barium Hexaferrite Nanoparticles Synthesized by Auto-Combustion Sol–Gel Processing

“…The spectra exhibit an O-H bending band of the H 2 O molecules chemically adsorbed to the magnetic particle surface around 1620 cm −1 . The absorption bonds around 3200-3500 cm −1 correspond to the O-H stretching mode which is represented by a broad band, where freely vibrating OH groups and hydrogen-bonded OH groups are apparent [11,16]. The peaks around 2850 and 2920 cm −1 can be attributed to the presence of C-H stretching [17].…”

“…The main features of the spectra include bands corresponding to barium hexaferrite and the OH group. The peaks in the ranges 420-450 and 540-600 cm −1 can be attributed to the stretching vibration of the metal-oxygen bond indicating the formation of a hexaferrite structure including octahedral and tetrahedral sites, respectively [11,13,16]. On the other hand, the wavenumber is inversely proportional to the atomic weight; hence, with the increasing substitution of Al 3+ ion contents, the peaks shift to a higher wavenumber (from 582 to 599 cm −1 ) due to Fe 3+ ions with a heavier atomic weight than Al 3+ ions and it confirms that the Al 3+ ions are entered to the lattice of BaFe 12 O 19 [6].…”

A review on MnZn ferrites: Synthesis, characterization and applications

“…MnZn ferrites are most suitable for their use in the microwave devices because of high permittivity, high resistivity, high stability, high value of saturation magnetization, high curie temperature with low eddy current and low magnetic losses [246,247]. Due to the use of ferrite nanomaterials, electronic devices can be mechanically hard, chemically stable and permit the materials to operate properly at a wide frequency range [248]. There are a lot of advantages of the use of MnZn ferrites in the microwave devices.…”