scholarly journals Study of the influence of conditions of synthesis on magnetic characteristics of composite materials based on iron powders

2020 ◽  
Vol 65 (1) ◽  
pp. 17-24
Author(s):  
A. K. Vetcher ◽  
G. A. Govor ◽  
K. I. Yanushkevich ◽  
U. T. Berdiev ◽  
F. F. Khasanov
Keyword(s):  
Composite Materials ◽  
Magnetization Reversal ◽  
Metallic Iron ◽  
Low Frequency ◽  
Hysteresis Loops ◽  
Inert Atmosphere ◽  
Magnetic Characteristics ◽  
Pressing Method ◽  
Iron Powders ◽  
Synthesis Conditions

The influence of synthesis conditions on the magnetic characteristics of composite materials based on iron powders ASC 100.29 (Sweden) and LiaoNing (China) is investigated. The surface of metallic iron powders is encapsulated by an insulating ferrite coating, consisting of iron oxides and phosphides. The synthesis was carried out at a temperature of 150 °C from a gaseous medium in a special reactor at a pressure of 1 atm. Insulating oxide coatings were applied both to the initial iron powder without treatment, and to previously annealed powders in an inert atmosphere and in a mixture of hydrogen-argon. To conduct studies of magnetic characteristics, cores in the form of rings were made by pressing method. The dependence of induction vs. magnitude of the magnetic field, magnetization reversal losses (hysteresis losses) in the full and in the private loop were recorded by an express magnetometer. The value of losses was calculated by the hysteresis loops area. The results show that composite low-frequency magnetic materials based on metallic iron ASC 100.29 and LiaoNing powders have similar values of magnetic parameters – almost identical B = f(H) dependencies, but the magnetization reversal losses for ASC 100.29 are significantly lower than for LiaoNing powder under equal insulating coatings synthesis conditions. It is possible to use such materials as magnetic cores in various electrical devices, such as cores of high-frequency transformers and a number of electrical machines. Since such materials can operate at frequencies from 1 kHz and higher, this will significantly reduce the overall dimensions and increase the efficiency of electrical products.

scholarly journals Micromagnetic Simulations of Fe and Ni Nanodot Arrays Surrounded by Magnetic or Non-Magnetic Matrices

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 349
Author(s):  
Devika Sudsom ◽  
Andrea Ehrmann
Keyword(s):  
Magnetic Materials ◽  
Data Storage ◽  
Magnetization Reversal ◽  
Hysteresis Loops ◽  
Object Oriented ◽  
Basic Research ◽  
Memory Systems ◽  
The Other ◽  
Micromagnetic Simulations ◽  
Nanodot Arrays

Combining clusters of magnetic materials with a matrix of other magnetic materials is very interesting for basic research because new, possibly technologically applicable magnetic properties or magnetization reversal processes may be found. Here we report on different arrays combining iron and nickel, for example, by surrounding circular nanodots of one material with a matrix of the other or by combining iron and nickel nanodots in air. Micromagnetic simulations were performed using the OOMMF (Object Oriented MicroMagnetic Framework). Our results show that magnetization reversal processes are strongly influenced by neighboring nanodots and the magnetic matrix by which the nanodots are surrounded, respectively, which becomes macroscopically visible by several steps along the slopes of the hysteresis loops. Such material combinations allow for preparing quaternary memory systems, and are thus highly relevant for applications in data storage and processing.

scholarly journals Asymmetric Magnetization Reversal in Exchange-Biased Hysteresis Loops

2000 ◽  
Vol 84 (17) ◽  
pp. 3986-3989 ◽  
Author(s):  
M. R. Fitzsimmons ◽  
P. Yashar ◽  
C. Leighton ◽  
Ivan K. Schuller ◽  
J. Nogués ◽  
...  
Keyword(s):  
Magnetization Reversal ◽  
Hysteresis Loops

Characterization of TMR Head Durability against Lapping Based on Magnetic Performance

2012 ◽  
Vol 523-524 ◽  
pp. 961-966
Author(s):  
Hideaki Tanaka ◽  
Yukio Maeda
Keyword(s):  
Ion Beam ◽  
Hysteresis Loops ◽  
Areal Density ◽  
Noise Spectrum ◽  
Crystallographic Analysis ◽  
Magnetic Characteristics ◽  
Ion Beam Etching ◽  
Verification Method ◽  
Magnetic Performance

Magnetic recording technologies are continuing to advance toward higher areal densities, driven by the availability of tunneling magnetoresistive (TMR) heads. However, high areal density heads require smaller physical dimensions, and this can render TMR heads more vulnerable to mechanical stresses generated during the lapping process. Although is important to verify the durability of TMR heads against lapping, it is very difficult to perform a crystallographic analysis of the affected layer because of the small dimensions involved. In this study, we attempted to establish an advanced TMR head verification method based on a magnetic performance analysis involving micro-Kerr hysteresis loops and the magnetic noise spectrum. We found that the magnetic performance changed when nanoscale scratches were removed from the lapped surface using ion beam etching. This indicates that the lapping process produces an affected layer which deteriorates the magnetic characteristics of the TMR head. A correlation was also found between the change in magnetic performance and the morphology of lapped surface.

Determination of Electric and Magnetic Properties of Commercial LTCC Soft Ferrite Material

2011 ◽  
Vol 8 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Nelu Blaž ◽  
Andrea Marić ◽  
Goran Radosavljević ◽  
Nebojša Mitrović ◽  
Ibrahim Atassi ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Low Frequency ◽  
Hysteresis Loops ◽  
Frequency Range ◽  
Dispersion Parameters ◽  
Simple Method ◽  
Component Design ◽  
Microwave Engineering ◽  
Characterization Procedure

This paper offers an effective, accurate, and simple method for permittivity and permeability determination of an LTCC (low temperature cofired ceramic) ferrite sample. The presented research can be of importance in the fields of ferrite component design and application, as well as for RF and microwave engineering. The characterization sample is a stack of LTCC tapes forming a toroid. Commercially available ferrite tape ESL 40012 was used and standard LTCC processing was applied for the sample fabrication. For the first time, the electrical properties of a ferrite toroid sample of ESL 40012 LTCC ferrite tape is presented at various frequencies. The electrical properties of LTCC ferrite materials, permittivity and specific resistivity, are shown in a frequency range from 10 kHz to 1 MHz using the capacitive method. The hysteresis properties of this material are also determined. B-H hysteresis loops were measured applying a maximum excitation of 2 kA/m and frequencies of 50 Hz, 500 Hz, and 1000 Hz. Permeability is determined in the frequency range from 10 kHz to 1 GHz and a characterization procedure is divided in two segments, for low and high frequencies. Low frequency measurements (from 10 kHz to 1 MHz) are performed using LCZ meter and discrete turns of wire, while a short coaxial sample holder and vector network analyzer were used for the higher frequency range (from 300 kHz to 1 GHz). In addition, another important factor required for the practical design of devices is presented, the temperature variation of the permeability dispersion parameters.

scholarly journals Developing a reference material set for the magnetic properties of NdFeB alloy-based hard magnetic materials

2019 ◽  
Vol 15 (1) ◽  
pp. 21-27
Author(s):  
E. A. Volegova ◽  
T. I. Maslova ◽  
V. O. Vas’kovskiy ◽  
A. S. Volegov
Keyword(s):  
Magnetic Properties ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Magnetic Loss ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Hysteresis Loop ◽  
Magnetic Characteristics ◽  
Hard Magnetic Materials ◽  
Certified Values

Introduction The introduction indicates the need for the use of permanent magnets in various technology fields. The necessity of measuring the limit magnetic hysteresis loop for the correct calculation of magnetic system parameters is considered. The main sources of error when measuring boundary hysteresis loops are given. The practical impossibility of verifying blocks of magnetic measuring systems element-by-element is noted. This paper is devoted to the development of reference materials (RMs) for the magnetic properties of hard magnetic materials based on Nd2Fe14B, a highly anisotropic intermetallic compound.Materials and measuring methods Nd-Fe-B permanent magnets were selected as the material for developing the RMs. RM certified values were established using a CYCLE‑3 apparatus included in the GET 198‑2017 State Primary Measurement Standard for units of magnetic loss power, magnetic induction of constant magnetic field in a range from 0.1 to 2.5 T and magnetic flux in a range from 1·10–5 to 3·10–2 Wb.Results and its discussion Based on the experimentally obtained boundary hysteresis loops, the magnetic characteristics were evaluated, the interval of permitted certified values was set, the measurement result uncertainty of certified values was estimated, the RM validity period was established and the first RM batch was released.Conclusion On the basis of conducted studies, the RM type for magnetic properties of NdFeB alloy-based hard magnetic materials was approved (MS NdFeB set). The developed RM set was registered under the numbers GSO 11059–2018 / GSO 11062–2018 in the State RM Register of the Russian Federation.

scholarly journals Spectral Characteristics of Acoustic Emission in Carbon Fiber-Reinforced Composite Materials Subjected to Cyclic Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Vladimir L. Shkuratnik ◽  
Petr V. Nikolenko
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Spectral Characteristics ◽  
Spectral Composition ◽  
Low Frequency ◽  
Sharp Change ◽  
Kaiser Effect ◽  
Emission Activity ◽  
The Time Domain

The article is devoted to the investigation of the spectral characteristics of acoustic emission signals that appear under various schemes of composite materials loading. The tests involved samples of composites reinforced with layers sheets of carbon fiber fabric and dispersed carbon fibers. Based on the results of laboratory tests, a comparison is made between the traditional parameters of acoustic emission and the complete spectrograms of the acoustic emission response developed with the use of a special algorithm. The relationship between the emission activity and the change in the spectral composition of emission hits is shown. For example, for some composites, the acoustic emission memory effect (Kaiser effect) manifests itself not only in the time domain but also in the spectral domain in a form of a sharp change in the amplitudes in the frequency range 130/150 kHz. Also, when the samples were loaded according to the Brazilian scheme, the presence of the so-called “inverse” Kaiser effect is observed, in which the memory carrier “remembers” the previously experienced level of tensile stresses and reproduces this information during subsequent unloading. Such effect manifests itself in the form of a sharp change in the amplitudes in the low-frequency region of the spectrum.

scholarly journals Using Hilbert Transform in Diagnostic of Composite Materials by Impedance Method

2020 ◽  
Vol 64 (4) ◽  
pp. 334-342 ◽  
Author(s):  
Volodymyr Eremenko ◽  
Artur Zaporozhets ◽  
Vitalii Babak ◽  
Volodymyr Isaienko ◽  
Kateryna Babikova
Keyword(s):  
Composite Materials ◽  
Nondestructive Testing ◽  
Hilbert Transform ◽  
Instantaneous Frequency ◽  
Information Quality ◽  
Low Frequency ◽  
Mechanical Impedance ◽  
Phase Characteristic ◽  
Impedance Method ◽  
Materials Testing

The article is devoted to the problem of the increasing of information quality for the impedance method of nondestructive testing. The purpose of this article is to get for the pulsed impedance method of nondestructive testing the additional informative parameters. Instantaneous values of the information signal's amplitude is a sensitive parameter to the effects of interference, in particular friction, which necessitates the use of additional informative features. It was experimentally measured signals from defective and defectless areas of the test pattern. Using of the Hilbert transform gave possibility to determine phase characteristics of these signals and realize demodulation to extract a low-frequency envelope for further analysis of its shape. It was received the informative features as a result of researches. Among them are instantaneous frequency of a signal, the integral of a phase characteristic on the selected interval and the integral of a difference signal phase characteristics. In order to compare quality of the defect detection using selected parameters it was carried out evaluation of the testing result reliability for a product fragment made of a composite material. Considering the influence of the change in the mechanical impedance of the researched area on the phase-frequency characteristics of the output signal of the converter, it is proposed to use as the diagnostic signs: the instantaneous frequency and the value of the phase characteristic of the current signal for certain points in time. The proposed informative features enable to increase general reliability of composite materials testing by the pulsed impedance method.

Preparation and Magnetic Properties of Fe@SiO2 Soft Magnetic Composites

2020 ◽  
Vol 993 ◽  
pp. 638-645
Author(s):  
Shuai Feng ◽  
Yan An ◽  
Zong Xiang Wang ◽  
Kai Sun ◽  
Run Hua Fan
Keyword(s):  
Magnetic Properties ◽  
Sol Gel ◽  
Core Loss ◽  
Low Frequency ◽  
Magnetic Flux Density ◽  
Iron Particles ◽  
Soft Magnetic ◽  
Magnetic Composites ◽  
Insulating Layer ◽  
Iron Powders

In this work, the insulating SiO2 was coated successfully on the surface of reduced iron particles by a sol-gel method to decrease the core loss at low frequency. The scanning electron microscope images and elements analysis confirm that the surface of iron powders particles were covered by a thin insulating layer in the form of uniform core-shell structure. The samples were annealed at 400 °C in N2 atmosphere to obtain better magnetic properties. The annealed SMCs with 10 mL/h dropping rate of TEOS have optimum magnetic properties with low core loss Ps of 280.89 W/kg and high saturation magnetic flux density Bs of 1.038 T at 1000 Hz.

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