scholarly journals Preparation and Magnetic Properties of CoFe2O4 Oriented Fiber Arrays by Electrospinning

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3860
Author(s):  
Chen Cheng ◽  
Jianfeng Dai ◽  
Zengpeng Li ◽  
Wei Feng
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Hysteresis Loop ◽  
Magnetic Materials ◽  
Magnetic Moment ◽  
Easy Axis ◽  
Great Influence ◽  
Hysteresis Loops ◽  
Strong Anisotropy ◽  
Fiber Arrays

The morphology of magnetic materials has a great influence on the properties, which is attributed to the magnetic anisotropy of the materials. Therefore, it is worth studying the fabrication of the aligned fiber and the change of its domain distribution. Nanoparticles and nanofibers were prepared by the hydrothermal and electrospinning methods, respectively. At the same time, the arranged nanofibers were collected by the drum collecting device. After the same annealing at 700 °C, it was found that the diameter of fibers collected by different collecting drums is similar. By studying the hysteresis loops of nanoarrays, it was found that they had strong anisotropy. The easy axis was parallel to the long axis, the Hc and Mr of the easy axis and the hard axis were 1330.5 Oe, 32.39 Am2/kg, and 857.2 Oe, 24.8 Am2/kg, respectively. Due to the anisotropy of the shape and the interaction between the particles, the Hc could not be enhanced. Therefore, the Ms and Hc of the nanoparticles were 80.23 Am2/kg and 979.3 Oe, respectively. The hysteresis loop and the change of magnetic moment during the demagnetization of the CoFe2O4 nanofiber array were simulated via micromagnetic software. The simulated Hc was 1480 Oe, which was similar to the experimental value.

scholarly journals OBTAINING HYSTERESIS LOOPS AT LOW FREQUENCY FOR CHARACTERIZATION OF MATERIALS TO BE USED IN BIOMEDICAL APPLICATIONS

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Atika Arshad ◽  
Rumana Tasnim ◽  
Sheroz Khan ◽  
A.H.M Zahirul Alam
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Hysteresis Loop ◽  
Magnetic Materials ◽  
Research Work ◽  
Low Frequency ◽  
Hysteresis Loops ◽  
Simple Circuit ◽  
Characterization Of Materials

The promising development of magnetic sensors in biomedical field demands an appropriate level of understanding of the magnetic properties of the materials used in their fabrication. To date only few of the types of magnetic materials are encountered where their magnetic properties, characterization techniques and magnetization behavior are yet to be explored more suitably in the light of their applications. This research work studies the characterization of materials by using a cost effective and simple circuit consisting of inductive transducer and an OP-AMP as a voltage integrator. In this approach the circuit was simulated using PSPICE and experiments have been conducted to achieve the desired results. The simulation and experimental results are obtained for three test materials namely iron, steel and plastic. The novelty lies in applying the simple circuit for material testing and characterization via obtaining simulation results and validating these results through experiment. The magnetic properties in low external magnetic field are studied with materials under test. The magnetization effect of a magneto-inductive sensor is detected in low frequency range for different magnetic core materials. The results have shown magnetization behaviour of magnetic materials due to the variation of permeability and magnetism. The resulted hysteresis loops appeared to have different shapes for different materials. The magnetic hysteresis loop found for iron core demonstrated a bigger coercive force and larger reversals of magnetism than these of steel core, thus obtaining its magnetic saturation at a larger magnetic field strength. The shape of the hysteresis loop itself is found to be varying upon the nature of the material in use. The resulted magnetization behaviors of the materials proved their possible applicability for use in sensing devices. The key concern of this work is found upon selecting the appropriate magnetic materials at the desired frequency of operation for magneto resistive applications, magneto-resistive sensors and for an extensive range of biomedical sensor application. 

scholarly journals Magnetization curves and hysteresis loops of nanostructured rare earth titanates

2018 ◽  
Vol 185 ◽  
pp. 03005
Author(s):  
Anatoly B. Rinkevich ◽  
Alexander V. Korolev ◽  
Mikhail I. Samoilovich ◽  
Sergej O. Demokritov ◽  
Dmitry V. Perov
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Hysteresis Loop ◽  
Magnetic Moment ◽  
Effective Magnetic Moment ◽  
Pyrochlore Structure ◽  
Hysteresis Loops ◽  
Nanocomposite Materials ◽  
Magnetization Curves ◽  
Crossing Point

Magnetic properties of the nanocomposite materials containing particles of rare earth titanates with pyrochlore structure have been investigated. For the nanocomposites with Gd2Ti2O7, La2Ti2O7 it has been observed that the effective magnetic moment in the nanocomposites differs substantially from that for Gd3+ and La3+ ions. The hysteresis loops was obtained for the nanocomposites with Dy3+, Gd3+, Yb3+, Er+, Sm3+ ions. There is no hysteresis loops for the nanocomposites with La2Ti2O7, Pr2Ti2O7 and Nd2Ti2O7 particles. It has been shown that nanocomposites with Yb2Ti2O7, Dy2Ti2O7 and Er2Ti2O7 particles have one crossing point on the descending branches of hysteresis loop in some temperature range.

Multiscale Magnetic Anisotropy in Amorphous Ferromagnetic Ribbon: An Example of FeCuNdSiB Alloy

2020 ◽  
Vol 312 ◽  
pp. 275-280
Author(s):  
Nikita Ilin ◽  
Sergey Komogortsev ◽  
Vitaliy Ivanov ◽  
Galina S. Kraynova ◽  
Alexander Davydenko ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloy ◽  
Magnetic Anisotropy ◽  
Hysteresis Loop ◽  
Domain Structure ◽  
Easy Axis ◽  
Anisotropy Constant ◽  
Rolling Axis ◽  
Magnetic Anisotropy Constant ◽  
Amorphous Ribbons

An understanding of the magnetic properties in an amorphous alloy requires comprehensive studies of magnetic anisotropy at various scales. In this paper such a study is carried out using amorphous ribbons FeCuNbSiB. The magnetic anisotropy associated with the rolling axis of ribbons does not affect hysteresis loop measurements, but the disappearance of a fingerprint-like pattern in the domain structure occurs in different fields when they are applied along and transverse the rolling axis. A correlation between the local magnetic anisotropy constant and the nanoscale within which the local easy axis is ordered was found.

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.

Coligand effects on the architectures and magnetic properties of octahedral cobalt(ii) complexes with easy-axis magnetic anisotropy

CrystEngComm ◽  
2020 ◽  
Vol 22 (13) ◽  
pp. 2297-2303 ◽  
Author(s):  
Yuewei Wu ◽  
Jing Xi ◽  
Jinhui Yang ◽  
Weiming Song ◽  
Shuchang Luo ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Easy Axis

Coligand effects lead to two mononuclear octahedral Co(ii) complexes exhibiting easy-axis magnetic anisotropies and distinct magnetic properties.

Magnetic Properties of Fe/Ru and Fe/Ir Superlattices with Short Periodicity

1991 ◽  
Vol 232 ◽  
Author(s):  
M. Piecuch ◽  
S. Andrieu ◽  
J. F. Bobo ◽  
M. Maurer ◽  
M. F. Ravet ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Magnetic Moment ◽  
Single Crystalline ◽  
Iron Base ◽  
First Case ◽  
Short Periodicity

ABSTRACTWe present new results on the magnetic properties of constrained, iron base, good quality, single-crystalline superlattices, Fe/Ru and Fe/Ir. It is shown that in the first case there are two magnetically dead layers at the interface while in the second case there is probably none. The magnetic moment of Fe is, in both superlattices, about 1.7μb. The magnetic anisotropy are opposite, in plane for Fe/Ru, perpendicular for Fe/Ir.

Investigation of Possible Uniaxial Anisotropy in Co11Zr2 Magnetic Phase

2020 ◽  
Vol 65 (1-2) ◽  
pp. 11-17
Author(s):  
R. Hirian ◽  
◽  
P. Palade ◽  
‪A. Ciorîță ◽  
S. Macavei ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
High Temperature ◽  
Magnetic Anisotropy ◽  
Magnetic Materials ◽  
Mechanical Milling ◽  
Magnetic Phase ◽  
Uniaxial Anisotropy ◽  
High Temperature Annealing ◽  
Hard Magnetic Materials

"The Co11Zr2 magnetic phase was obtained by a combination of melting, mechanical milling and high temperature annealing. The structure and magnetic properties of the obtained material were investigated. Even though the samples possessed low coercivity, it was shown that they possess uniaxial anisotropy. Keywords: hard magnetic materials, magnetic anisotropy, mechanical milling, high temperature annealing "

Magnetic anisotropy of Sm2Fe17−xGax hydrides

1993 ◽  
Vol 71 (11-12) ◽  
pp. 574-577 ◽  
Author(s):  
R. A. Dunlap ◽  
Z. Wang
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Room Temperature ◽  
Single Phase ◽  
Easy Axis ◽  
Phase 2 ◽  
Planar Anisotropy ◽  
Uniaxial Magnetic Anisotropy ◽  
Diffusion Of Hydrogen ◽  
Hard Magnetic Properties

The magnetic properties of single-phase 2:17 compounds of the composition Sm2Fe17−xGaxHy were investigated. The substitution of Ga for Fe in the Sm2Fe17 compound resulted in a substantial increase in the Curie temperature and, for alloys with x > 2, the formation of a uniaxial magnetic anisotropy at room temperature. The diffusion of hydrogen into those compounds that exhibit an easy axis anisotropy causes a transition back to a planar anisotropy. This indicates that the presence of interstitial hydrogen is detrimental to the hard magnetic properties of these materials.

scholarly journals Optimization of magnetic properties and GMI effect of Thin Co-rich Microwires for GMI Microsensors

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1558 ◽  
Author(s):  
Lorena Gonzalez-Legarreta ◽  
Paula Corte-Leon ◽  
Valentina Zhukova ◽  
Mihail Ipatov ◽  
Juan Maria Blanco ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Hysteresis Loops ◽  
Transverse Magnetic ◽  
Wide Frequency Range ◽  
Soft Magnetic ◽  
Giant Magnetoimpedance ◽  
Giant Magnetoimpedance Effect ◽  
Annealing Temperatures ◽  
High Annealing

Magnetic microwires can present excellent soft magnetic properties and a giant magnetoimpedance effect. In this paper, we present our last results on the effect of postprocessing allowing optimization of the magnetoimpedance effect in Co-rich microwires suitable for magnetic microsensor applications. Giant magnetoimpedance effect improvement was achieved either by annealing or stress-annealing. Annealed Co-rich presents rectangular hysteresis loops. However, an improvement in magnetoimpedance ratio is observed at fairly high annealing temperatures over a wide frequency range. Application of stress during annealing at moderate values of annealing temperatures and stress allows for a remarkable decrease in coercivity and increase in squareness ratio and further giant magnetoimpedance effect improvement. Stress-annealing, carried out at sufficiently high temperatures and/or stress allowed induction of transverse magnetic anisotropy, as well as magnetoimpedance effect improvement. Enhanced magnetoimpedance ratio values for annealed and stress-annealed samples and frequency dependence of the magnetoimpedance are discussed in terms of the radial distribution of the magnetic anisotropy. Accordingly, we demonstrated that the giant magnetoimpedance effect of Co-rich microwires can be tailored by controlling the magnetic anisotropy of Co-rich microwires, using appropriate thermal treatment.

scholarly journals Effect of the Substrate Crystallinity on Morphological and Magnetic Properties of Fe70Pd30 Nanoparticles Obtained by the Solid-State Dewetting

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7420
Author(s):  
Gabriele Barrera ◽  
Federica Celegato ◽  
Matteo Cialone ◽  
Marco Coïsson ◽  
Paola Rizzi ◽  
...  
Keyword(s):  
Thin Film ◽  
Magnetic Properties ◽  
Solid State ◽  
Magnetic Materials ◽  
Low Cost ◽  
Chemical Properties ◽  
Hysteresis Loops ◽  
Morphological Transformation ◽  
Dewetting Process ◽  
Average Size

Advances in nanofabrication techniques are undoubtedly needed to obtain nanostructured magnetic materials with physical and chemical properties matching the pressing and relentless technological demands of sensors. Solid-state dewetting is known to be a low-cost and “top-down” nanofabrication technique able to induce a controlled morphological transformation of a continuous thin film into an ordered nanoparticle array. Here, magnetic Fe70Pd30 thin film with 30 nm thickness is deposited by the co-sputtering technique on a monocrystalline (MgO) or amorphous (Si3N4) substrate and, subsequently, annealed to promote the dewetting process. The different substrate properties are able to tune the activation thermal energy of the dewetting process, which can be tuned by depositing on substrates with different microstructures. In this way, it is possible to tailor the final morphology of FePd nanoparticles as observed by advanced microscopy techniques (SEM and AFM). The average size and height of the nanoparticles are in the ranges 150–300 nm and 150–200 nm, respectively. Moreover, the induced spatial confinement of magnetic materials in almost-spherical nanoparticles strongly affects the magnetic properties as observed by in-plane and out-of-plane hysteresis loops. Magnetization reversal in dewetted FePd nanoparticles is mainly characterized by a rotational mechanism leading to a slower approach to saturation and smaller value of the magnetic susceptibility than the as-deposited thin film.

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