Structural and magnetic properties of yttrium iron garnet (YIG) and yttrium aluminum iron garnet (YAlG) nanoferrite via sol-gel synthesis

The structural and magnetic properties of yttrium iron garnet (YIG) and yttrium aluminum iron garnet (Y3AlxFe5−xO12, YAIG) (x = 0.2, 0.6, 1, 1.4, 1.8, and 2.2) nanoparticles were investigated. The samples were prepared via auto combustion sol-gel technique, using citric acid as chelating agent and fuel for the combustion process. The obtained powder was heated at 950 °C. X-ray diffraction peaks confirmed the garnet phase formation. Crystallite size increases with Al from 28.5894 to 28.6170 nm. Lattice constant of the samples was found to decrease from 12.4674 Å to 12.3233 Å as Al increase from 0.0 to 2.2. FTIR was used to confirm the garnet structure, the main vibrating modes were observed to shift to higher wave number with increasing Al concentration. Saturation magnetization, Ms shows a decreasing trend from 20.721 to 0.7586 emu/g with increasing Al from 0.0 to 2.2. Furthermore, the decreasing trends in the static magnetic properties of YAIG samples may be due to the introduction of Al ions in the YIG crystal lattice. High content of Al substitution on YIG leads to paramagnetic behavior of the ferrite. The grain size decreased from 0.64 μm to 0.32 μm, while the bulk density decreased from 5.058 gcm−3 to 4.233 gcm−3 as Al increase from 0.0 to 2.2

Influence of aluminum substitution on microstructural, electrical, dielectric and electromagnetic properties of sol-gel synthesized yttrium iron garnet (YlG)

Aluminum-substituted Yttrium iron garnet, Al-YIG (Y3AlxFe5-xO12; x = 0.4, 0.8, 1.2, 1.6 and 2.0) samples were synthesized via auto combustion sol-gel technique. The obtained powder was heated at 950 °C, pressed into pellets and sintered at 1200 oC. The samples microstructures were studied using Field emissions scanning electron microscopy (FESEM). The average grain size decreased from 0.46 µm at x = 0.4 to a minimum value of 0.33 µm at x = 2.0. Elemental composition of the samples was studied by energy dispersive x-ray (EDX), while bulk density was measured by Archimedes principle. Electrical and dielectric measurements were carried out using Agilent impedance analyzer. Generally, the samples resistivity decreased with Al concentration. At 1 MHz frequency, the sample x = 0.4 has the highest resistivity of 2.19 × 105 Ωm which decreases down to its minimum value of 1.75 × 104 Ωm at x = 2.0. The dielectric constant for all the samples decreased with frequency. For the sample x = 0.4, the ε'r decreased from 49.03 at 40 Hz to 8.08 at 1 MHz. The dielectric loss tangent, tan δ decreased with increasing frequency, while it increased with Al substitution. Permeability values were calculated from permittivity data. The real ermeability decreases from 1263.12 at x = 0.4 to 6.96 at x = 1.2, and the decreased down to 11.74 at x = 2.0. The high dielectric constant, low resistivity and low loss values of the samples indicate their suitability for miniaturization of radio frequency devices, antenna and filter resonator

Synthesis and characterization of barium hexaferrites derived from steel waste by ammonium nitrate salt melt synthesis

In this paper, a series of barium hexaferrite BaFe12O19 with different powder to salt ratio (1:3, 1:4, 1:5) were prepared using ammonium salt melt technique. Iron oxide were process from steel waste product were mixed with barium carbonate, used as starting materials to produce barium hexaferrites. The ammonium nitrates in this experiment act as oxidizing agent in this synthesis. The BaFe12O19 powders were sintered at 1300°C for six hours and characterized using X-ray diffraction (XRD), Fourier transform Infrared (FTIR), Vibrating Sample Magnetometer (VSM) and Field emission Scanning Microscope (FeSEM) to investigate its crystallography, magnetic properties and morphology. The maximum coercivity and saturation magnetization obtained for sample ratio 1:3 of 1017 G and 90.9 emu/g, respectively. Increase the salt ratio decrease the coercivity and saturation magnetization values

Structural and magnetic properties of aluminum substituted yttrium iron garnet via sol-gel synthesis

Aluminum-substituted yttrium iron garnet (Al-YIG) powders was synthesize by using sol-gel citrate nitrate combustion technique with different doping concentration (x = 0.4, 0.6 and 1.0). The Y3-x Alx Fe5O12 samples were analyse of phase, structural and hysteresis by using X-ray diffraction (XRD), Fourier transform infra-red (FTIR) and Vibrating Sample Magnetometer (VSM).The powder resulted a single phase nanostructured garnet was formed. Room temperature saturation magnetization Ms and coercivity of Al-YIG powders decreased as a function of increasing Al content. The samples has a room temperature Ms of 9.2 emu/g and decreased to 1.5 emu/g. Coercivity Hc value decreases from 71.7 G to 51.4 G

Composition and magnetic properties of aluminium substituted yttrium iron garnet waste mill scales derived via mechanical alloying technique

This paper presents the effects of aluminium substitution on sample composition, density and magnetic properties of yttrium iron garnet, Y3Fe5O12 (YIG). Mill scales, in a form of flakes was obtained from the steel industry in Malaysia. The mill scales was purified to produce high purity hematite, Fe2O3. The mill scales derived Fe2O3 were used as raw material to prepare the aluminum substituted yttrium iron garnet Y3Fe(5-x) Al(x) O12 (Al-YIG) with variation compositional x = 0.0, 0.5, 1.0, 1.5 and 2.0 using mechanical alloying technique. X-ray fluorescence (XRF) was used to investigate the percentage compositions of the raw mill scales. The magnetic hysteresis of sample were investigate by using B-H tracer (MATS). Density of the Al-YIG bulk samples was found to decrease with increasing xAl2O3 content. The saturation magnetization Ms also shows a decrease with increase xAl2O3 content. The maximum saturation magnetization Ms and coercivity Hc was found at 310 G and 14.98 Oe, respectively. With increase xAl2O3 to 2.0%, the Ms and Hc were reduced to 29.35 G and 3.15 Oe, respectively

Structural and magnetic properties of SRM0.5FE11.5O19 (M: TI4+, CO2+, NI2+, CU2+, and ZN2+) derived from steel waste product via mechanical alloying

This paper presents the steel waste product used as the main source of raw material in the preparation of permanent magnets ferrites, substitution with transition metal cation. M-type hexaferrites of SrM0.5Fe11.5O19 (M: Ti, Co, Ni, Cu, and Zn) component were investigated. Samples were prepared by Mechanical Alloying (MA) process and analysis microstructure of samples were characterized by using X-ray Diffraction (XRD). The specific saturation magnetization Ms, the coercivity Hc and remanence Mr was carried out using B–H hysteresis measurement. The XRD patterns show single phase of the magnetoplumbite strontium ferrite and Fe2O3 phases were only present in Ti4+ substitution. Significant increase in calculated lattice parameter a, c and cell volume Vcell from XRD indicating solubility of substituted cation in hexagonal structure of strontium ferrite. Magnetization measurements discovered that saturation magnetization Ms of the all samples proportional to magnetic moment μB of substituted cation with highest 28.33 emu/g from Co2+.While highest coercivity 26.5 kA/m from Co2+ and for remanence Zn2+ 0.955 Tesla. The magnetic properties such as remanence Br and coercivity Hc make the synthesized materials useful for high density recording media and permanent magnets

Magnetic,structural and electrical properties of aluminium-substituted Yttrium iron garnet (Y₃Fe₅- AlᵪO₁₂ with X=0, .., 3.0) prepared via auto-combustion sol-gel method

YIG ferrite material has been attracting attention due to its high electric resistivity, high radiation stability, comparatively low magnetization, narrowest ferromagnetic line width and consequent low loss. In this work, aluminum-substituted Yttrium iron garnet, (Y3Fe5-xAlxO12) powders, with x = 0, 0.2, 0.4, 0.6, to 3.0 were prepared using auto-combustion sol-gel method. The structural, magnetic and dielectric properties, at radio frequency range, were studied so as to contribute towards the study and improvement of microwave communication materials. The X-ray diffraction (XRD) revealed the most representative peaks for YIG structure (400), (420) and (422) sharply reflected as matched by ICSD data. However, single garnet phase was found to be limited to 0.6 ≤ x ≤ 1.6. The morphology of the samples, studied by Field Emission Scanning Electron Microscope (FESEM) shows decreasing grain sizes as Al concentration increases. Magnetic properties of the samples were studied using vibrating sample magnetometer (VSM). Saturation magnetization, Ms was observed to decrease from 20.721 emu/g to 0.8112 emu/g as x increases from 0 to 3.0, while remnance magnetization, Mr decreased from 2.23 emu/g at x = 0, to 0 emu/g at x = 1.8 and above. The Coercivity, Hc changed non-linearly with x, having a maximum value of 39.00 Oe at x = 0.8 and a minimum value of 0 Oe at x ≥ 1.8. Dielectric properties of the samples were obtained at room temperature using Agilent impedance analyzer. At 1 MHz, the dielectric constant, εr of the samples decreases from its maximum value of 36.911 at x = 0 to its minimum value of 5.63 at x = 0.6. Dielectric loss tangent, tan δ has a minimum value of 0.016 at x = 3.0 and a maximum value of 0.184, while the pure sample has a value of 0.027 at 1 MHz. The conductivity decreased from 5.902 x 10-5 Sm-1 at x = 0 to its minimum value of 4.5 x 10-6 for x = 0.4, and increased thereafter, while the resistivity shows a reversed trend. The magnetic permeability, μ shows a decreasing trend increasing frequency. At 1 MHz, the value increased from 26.75 at x = 0 to 1263.12 at x = 0.4, while magnetic loss tangent, tan μ decreased from 0.029 to 0.0096 as x increases from 0 to 0.4. From the result, it shows that the Al-YIG materials have good magnetic and dielectric properties, μr > 1, εr > 1, tan δ < 1and tan μ < 1. This is suitable for antenna miniaturization that can enhance the performance of radio wave communication devices

Effect of sintering temperature on crystallography and microstructure of yttrium iron garnet via mechanical alloying technique

This work focused on the preparation of yttrium iron garnet (Y3Fe5O12, YIG) via mechanical alloying technique derived by steel waste product. The steel waste was purified by using magnetic and non-magnetic particles (MNM) and Curie temperature separation (CTS) technique. The powder from the CTS technique was oxidized at 500°C for 9 hours in air to form the iron oxide (Fe2O3). The Fe2O3 was mixed with Y2O3 using high energy ball milling for 9 hours. The obtained mixed powder was pressed and sintered at varied temperature 500/600/700/800/900/1000/1100/1200 °C. X-ray diffraction (XRD) showed the YIG was completely formed at 1100°C. The crystallite size and grain size of YIG powder were observed. The results show the grain size and crystallite size increased as a function of sintering temperatures