Magnetic complex permeability (imaginary part) dependence on the microstructure of a Cu-doped Ni–Zn-polycrystalline sintered ferrite

2020 ◽  
Vol 46 (10) ◽  
pp. 14558-14566 ◽  
Author(s):  
A. Barba ◽  
C. Clausell ◽  
J.C. Jarque ◽  
L. Nuño
Keyword(s):  
Imaginary Part ◽  
Complex Permeability ◽  
Magnetic Complex

Structural and Microwave Properties of Copper Ferrite Nanoparticles Prepared by Sol-Gel Synthesis

2005 ◽  
Vol 23 ◽  
pp. 141-144 ◽  
Author(s):  
Thresiamma George ◽  
Sunny Joseph ◽  
Suresh Mathew
Keyword(s):  
Imaginary Part ◽  
Perturbation Technique ◽  
Sol Gel ◽  
Chelating Agent ◽  
Ferrite Nanoparticles ◽  
Microwave Cavity ◽  
Complex Permeability ◽  
Copper Ferrite ◽  
Dielectric Parameters ◽  
Sol Gel Synthesis

Copper ferrite nanoparticles are prepared by sol-gel synthesis using polyacrylic acid (PAA) as chelating agent. The crystal structure and surface morphology are studied by XRD and SEM techniques. Microwave dielectric parameters such as real and imaginary part of complex permittivity and a.c. conductivity are determined in the frequency range 2247 - 2970 MHz by microwave cavity perturbation technique. Microwave magnetic parameters such as the real and imaginary part of complex permeability are also determined.

Preparation and Microwave Absorption Property of Nickel Spinel Ferrite

2012 ◽  
Vol 531-532 ◽  
pp. 36-39
Author(s):  
Yuan Liu ◽  
Xiang Xuan Liu ◽  
Ze Yang Zhang
Keyword(s):  
Citric Acid ◽  
Microwave Absorption ◽  
Imaginary Part ◽  
Combustion Temperature ◽  
Structural Characteristics ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Complex Permeability ◽  
Microwave Absorbing ◽  
Absorbing Property

NiFe2O4 ferrite was synthesized by sol-gel method. Its structural characteristics, morphology, electromagnetic and microwave absorption properties were analyzed by X-ray diffraction, scanning electron microscope and network analyzer, and analyzed the influence of the combustion temperature and citric acid. The results indicated that the particle size be enlarged with an increased combustion temperature and be diminished first, then increased with the increased of citric acid, and the best ratio of citric acid with metal ions for nCA: nFe: nNi = 4:2:1. Its microwave absorbing property is increased with the increased combustion temperature. Its complex permittivity imaginary part first decreases with temperature increases and then increases, the imaginary part of complex permeability with increasing temperature increases, indicating that the increase of calcination temperature, help to improve the sample microwave absorbing properties.

Effect of Complex Permeability on Circuit Parameters of CPW with Magnetic Noise Suppression Sheet

2020 ◽  
Vol E103.B (9) ◽  
pp. 899-902
Author(s):  
Sho MUROGA ◽  
Motoshi TANAKA ◽  
Takefumi YOSHIKAWA ◽  
Yasushi ENDO
Keyword(s):  
Noise Suppression ◽  
Complex Permeability ◽  
Magnetic Noise

scholarly journals Effects of Recycled Fe2O3 Nanofiller on the Structural, Thermal, Mechanical, Dielectric, and Magnetic Properties of PTFE Matrix

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2332
Author(s):  
Ahmad Mamoun Khamis ◽  
Zulkifly Abbas ◽  
Raba’ah Syahidah Azis ◽  
Ebenezer Ekow Mensah ◽  
Ibrahim Abubakar Alhaji
Keyword(s):  
Electron Microscopy ◽  
High Energy ◽  
Filler Loading ◽  
Complex Permeability ◽  
X Ray Diffraction ◽  
Thermal Expansion Coefficients ◽  
Transmission Electron ◽  
Energy Ball ◽  
Hematite Fe2o3 ◽  
Ptfe Composites

The purpose of this study was to improve the dielectric, magnetic, and thermal properties of polytetrafluoroethylene (PTFE) composites using recycled Fe2O3 (rFe2O3) nanofiller. Hematite (Fe2O3) was recycled from mill scale waste and the particle size was reduced to 11.3 nm after 6 h of high-energy ball milling. Different compositions (5–25 wt %) of rFe2O3 nanoparticles were incorporated as a filler in the PTFE matrix through a hydraulic pressing and sintering method in order to fabricate rFe2O3–PTFE nanocomposites. The microstructure properties of rFe2O3 nanoparticles and the nanocomposites were characterized through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). The thermal expansion coefficients (CTEs) of the PTFE matrix and nanocomposites were determined using a dilatometer apparatus. The complex permittivity and permeability were measured using rectangular waveguide connected to vector network analyzer (VNA) in the frequency range 8.2–12.4 GHz. The CTE of PTFE matrix decreased from 65.28×10−6/°C to 39.84×10−6/°C when the filler loading increased to 25 wt %. The real (ε′) and imaginary (ε″) parts of permittivity increased with the rFe2O3 loading and reached maximum values of 3.1 and 0.23 at 8 GHz when the filler loading was increased from 5 to 25 wt %. A maximum complex permeability of 1.1−j0.07 was also achieved by 25 wt % nanocomposite at 10 GHz.

scholarly journals Opacity from Loops in AdS

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Alexandria Costantino ◽  
Sylvain Fichet
Keyword(s):  
Imaginary Part ◽  
Quantum Dynamics ◽  
Model Building ◽  
Asymptotic Properties ◽  
The Self ◽  
Effective Theory ◽  
Self Energy ◽  
Higher Dimensional ◽  
Timelike Region ◽  
Spectral Representations

Abstract We investigate how quantum dynamics affects the propagation of a scalar field in Lorentzian AdS. We work in momentum space, in which the propagator admits two spectral representations (denoted “conformal” and “momentum”) in addition to a closed-form one, and all have a simple split structure. Focusing on scalar bubbles, we compute the imaginary part of the self-energy ImΠ in the three representations, which involves the evaluation of seemingly very different objects. We explicitly prove their equivalence in any dimension, and derive some elementary and asymptotic properties of ImΠ.Using a WKB-like approach in the timelike region, we evaluate the propagator dressed with the imaginary part of the self-energy. We find that the dressing from loops exponentially dampens the propagator when one of the endpoints is in the IR region, rendering this region opaque to propagation. This suppression may have implications for field-theoretical model-building in AdS. We argue that in the effective theory (EFT) paradigm, opacity of the IR region induced by higher dimensional operators censors the region of EFT breakdown. This confirms earlier expectations from the literature. Specializing to AdS5, we determine a universal contribution to opacity from gravity.

scholarly journals The Structure and Magnetic Properties of Rapidly Quenched Fe72Ni8Nb4Si2B14 Alloy

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 5
Author(s):  
Lukasz Hawelek ◽  
Tymon Warski ◽  
Patryk Wlodarczyk ◽  
Marcin Polak ◽  
Przemyslaw Zackiewicz ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Relaxation Process ◽  
Glassy State ◽  
Diffraction Method ◽  
Soft Magnetic Materials ◽  
Process Time ◽  
Complex Permeability ◽  
Soft Magnetic ◽  
Conventional Heat Treatment ◽  
Glass Relaxation

The complex structural and magnetic studies of the annealed rapidly quenched Cu-free Fe72Ni8Nb4Si2B14 alloy (metallic ribbons form) are reported here. Based on the calorimetric results, the conventional heat treatment process (with heating rate 10 °C/min and subsequent isothermal annealing for 20 min) for wound toroidal cores has been optimized to obtain the least lossy magnetic properties (for the minimum value of coercivity and magnetic core losses at 50 Hz). For optimal conditions, the complex permeability in the 104–108 Hz frequency range together with core power losses obtained from magnetic induction dependence up to the frequency of 400 kHz was successfully measured. The average and local crystal structure was investigated by the use of the X-ray diffraction method and the transmission electron microscopy observations and proved its fully glassy state. Additionally, for the three temperature values, i.e., 310, 340 and 370 °C, the glass relaxation process study in the function of annealing time was carried out to obtain a deeper insight into the soft magnetic properties: magnetic permeability and cut-off frequency. For this type of Cu-free soft magnetic materials, the control of glass relaxation process (time and temperature) is extremely important to obtain proper magnetic properties.

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