Micromagnetic Simulation on the Microwave Magnetic Properties of Glass-Coated Amorphous Alloy Microwires

2013 ◽  
Vol 668 ◽  
pp. 733-736
Author(s):  
Yong Jiang Di ◽  
Peng Jun Cao ◽  
Bi Jia ◽  
Jian Jun Jiang
Keyword(s):  
Finite Element Method ◽  
Magnetic Anisotropy ◽  
Magnetic Domain ◽  
Anisotropy Field ◽  
Magnetic Alloy ◽  
Microwave Resonance ◽  
Crystalline Anisotropy ◽  
Magnetic Spectrum ◽  
Simulation Results ◽  
Magneto Crystalline Anisotropy

The magnetic structure of the glass-coated magnetic alloy microwires were modeled based on the main magnetic domain structure and meshed by finite element method. The magnetic spectrum of the magnetic alloy microwires was calculated based on the micromagnetic theory. The simulation results of the magnetic spectrum of glass-coated magnetic alloy microwires showed that the magnetic anisotropy field increase as the magneto-crystalline anisotropy constants increase. The microwave resonance frequency increased accompanied by the reduction of the permeability and the increase of the magnetic anisotropy field of the glass-coated magnetic alloy microwires.

scholarly journals Magnetic Anisotropy of Dispersed Powders

1960 ◽  
Vol 13 (2) ◽  
pp. 196 ◽  
Author(s):  
FD Stacey
Keyword(s):  
Magnetic Anisotropy ◽  
Single Crystal ◽  
Ferromagnetic Material ◽  
Anisotropy Constant ◽  
Surprising Result ◽  
Inert Matrix ◽  
Crystalline Anisotropy ◽  
Iron Nickel ◽  
Small Grains ◽  
Magneto Crystalline Anisotropy

It is well known that in most rocks the ferromagnetic fraction occurs as small grains dispersed in a solid, magnetically inert matrix. Recently the magnetic anisotropy of rocks and of chondritic meteorites has been subjected to detailed study by the torque-meter method, and, in an attempt to obtain a physical understanding of the shape and crystal alignments of grains which cause magnetic anisotropy in these natural bodies, a number of artificial specimens have been prepared. Iron, nickel, and magnetite powders were mixed into solidifying media and allowed to set in a cylindrical mould in a 10 kilo-oersted field. The torque curves of the resulting specimens reveal a surprising result. It appears that single crystal magnetic grains tend to string together along lines of forc~, thus producing strongly anisotropic specimens, only when the first magneto crystalline anisotropy constant of the ferromagnetic material is positive.

scholarly journals The effect of magneto-crystalline anisotropy on the properties of hard and soft magnetic ferrite nanoparticles

2019 ◽  
Vol 10 ◽  
pp. 1348-1359 ◽  
Author(s):  
Hajar Jalili ◽  
Bagher Aslibeiki ◽  
Ali Ghotbi Varzaneh ◽  
Volodymyr A Chernenko
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Magnetic Behavior ◽  
Soft Magnetic ◽  
Interparticle Interactions ◽  
Co Doping ◽  
Heat Efficiency ◽  
Crystalline Anisotropy ◽  
Structure Morphology ◽  
Magneto Crystalline Anisotropy

Recent advances in the field of magnetic materials emphasize that the development of new and useful magnetic nanoparticles (NPs) requires an accurate and fundamental understanding of their collective magnetic behavior. Studies show that the magnetic properties are strongly affected by the magnetic anisotropy of NPs and by interparticle interactions that are the result of the collective magnetic behavior of NPs. Here we study these effects in more detail. For this purpose, we prepared Co x Fe3− x O4 NPs, with x = 0–1 in steps of 0.2, from soft magnetic (Fe3O4) to hard magnetic (CoFe2O4) ferrite, with a significant variation of the magnetic anisotropy. The phase purity and the formation of crystalline NPs with a spinel structure were confirmed through Rietveld refinement. The effect of Co doping on structure, morphology and magnetic properties of Co x Fe3− x O4 samples was investigated. In particular, we examined the interparticle interactions in the samples by δm graphs and Henkel plots that have not been reported before in literature. Finally, we studied the hyperthermia properties and observed that the heat efficiency of soft Fe3O4 is about 4 times larger than that of hard CoFe2O4 ferrite, which was attributed to the high coercive field of samples compared with the external field amplitude.

scholarly journals Investigation of Magnetic Anisotropy and Barkhausen Noise Asymmetry Resulting from Uniaxial Plastic Deformation of Steel S235

2021 ◽  
Vol 11 (8) ◽  
pp. 3600
Author(s):  
Martin Pitoňák ◽  
Miroslav Neslušan ◽  
Peter Minárik ◽  
Jiří Čapek ◽  
Katarína Zgútová ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Magnetic Anisotropy ◽  
Magnetic Coupling ◽  
Critical Threshold ◽  
Barkhausen Noise ◽  
Crystalline Anisotropy ◽  
The Asymmetry ◽  
Matrix Orientation ◽  
Magneto Crystalline Anisotropy ◽  
Insight Into

This study investigates alterations in magnetic anisotropy and the marked asymmetry in Barkhausen noise (MBN) signals after the uniaxial plastic straining of steel S235 obtained from a shipyard and used as standard structural steel in shipbuilding. It was found that the initial easy axis of magnetisation in the direction of previous rolling, and also in the direction of loading, becomes the hard axis of magnetisation as soon as the plastic strain attains the critical threshold. This behaviour is due to the preferential matrix orientation and the corresponding realignment of the magneto-crystalline anisotropy. Apart from the angular dependence of MBN, the asymmetry in the consecutive MBN bursts at the lower plastic strains is also analysed and explained as a result of magnetic coupling between the grains plastically strained and those unaffected by the tensile test. It was found that, by increasing the degree of plastic strain, the marked asymmetry in MBN tends to vanish. Moreover, the asymmetry in MBN bursts occurs in the direction of uniaxial tension and disappears in the perpendicular direction. Besides the MBN technique, XRD and EBSD techniques were also employed in order to provide a deeper insight into the investigated aspects.

Magnetic Anisotropy of Co-Nanostructures Embedded in Matrices with Different Pores Size and Morphology

2015 ◽  
Vol 233-234 ◽  
pp. 583-586 ◽  
Author(s):  
Elena Denisova ◽  
Lidia Chekanova ◽  
Rauf Iskhakov ◽  
Sergey Komogortsev ◽  
Ivan Nemtsev ◽  
...  
Keyword(s):  
Composite Materials ◽  
Magnetic Anisotropy ◽  
Anisotropy Field ◽  
X Ray Diffraction ◽  
Local Anisotropy ◽  
Polycarbonate Membrane ◽  
Crystalline Anisotropy ◽  
P Content ◽  
Polycarbonate Membranes ◽  
Size And Morphology

Composite materials with Co (P) particles embedded into pores of silica and track etched polycarbonate membranes were fabricated by an electroless reduction. The magnetic and structural properties of the composite materials are characterized by scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometer. The macroscopic and local magnetic anisotropy of the Co (P) particles electroless deposited in the pores of the polycarbonate membrane and silica is studied. The composite materials with linear pores exhibit uniaxial magnetic anisotropy. The easy axis lies along the Co (P) rods, the shape anisotropy dominates over the intrinsic crystalline anisotropy. Information on local anisotropy field and the grain size was obtained from investigation of approach to saturation magnetization law. The local anisotropy field for all the samples depends on P content. For Co (P) rods the local anisotropy value is also determined by nominal pore sizes. It was found that the investigated Co (P) rods is nanocrystalline. The effects of different pores morphology on the FMR-spectra characteristics are studied.

scholarly journals Structural and Magnetic Properties of Nanosized Barium Hexaferrite Powders Obtained by Microemulsion Technique

2010 ◽  
Vol 159 ◽  
pp. 57-62 ◽  
Author(s):  
Tatyana Koutzarova ◽  
Svetoslav Kolev ◽  
Kornely Grigorov ◽  
Chavdar Ghelev ◽  
Andrzej Zaleski ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Cetyltrimethylammonium Bromide ◽  
Room Temperature ◽  
Average Particle Size ◽  
Barium Hexaferrite ◽  
Anisotropy Field ◽  
Microemulsion System ◽  
Average Particle ◽  
Crystalline Anisotropy ◽  
Magneto Crystalline Anisotropy

Thin hexagonal barium hexaferrite particles synthesized using the microemulsion technique were studied. A water-in-oil reverse microemulsion system with cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, n-butanol as a co-surfactant, n-hexanol as a continuous oil phase, and an aqueous phase were used. The microstructural and magnetic properties were investigated. The particles obtained were mono-domain with average particle size 280 nm. The magnetic properties of the powder were investigated at 4.2 K and at room temperature. The saturation magnetization was 48.86 emu/g and the coercivity, 2.4 x 105 A/m at room temperature. The anisotropy field Ha and magneto-crystalline anisotropy K1 were 1.4 x 106 A/m and 2.37 x 105 J/m3, respectively.

scholarly journals Effect of large mechanical stress on the magnetic properties of embedded Fe nanoparticles

2011 ◽  
Vol 2 ◽  
pp. 268-275 ◽  
Author(s):  
Srinivasa Saranu ◽  
Sören Selve ◽  
Ute Kaiser ◽  
Luyang Han ◽  
Ulf Wiedwald ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Data Storage ◽  
Dominant Role ◽  
Magnetic Film ◽  
Biaxial Stress ◽  
Magnetic Data ◽  
Particle Volume ◽  
Crystalline Anisotropy ◽  
Magneto Crystalline Anisotropy

Magnetic nanoparticles are promising candidates for next generation high density magnetic data storage devices. Data storage requires precise control of the magnetic properties of materials, in which the magnetic anisotropy plays a dominant role. Since the total magneto-crystalline anisotropy energy scales with the particle volume, the storage density in media composed of individual nanoparticles is limited by the onset of superparamagnetism. One solution to overcome this limitation is the use of materials with extremely large magneto-crystalline anisotropy. In this article, we follow an alternative approach by using magneto-elastic interactions to tailor the total effective magnetic anisotropy of the nanoparticles. By applying large biaxial stress to nanoparticles embedded in a non-magnetic film, it is demonstrated that a significant modification of the magnetic properties can be achieved. The stress is applied to the nanoparticles through expansion of the substrate during hydrogen loading. Experimental evidence for stress induced magnetic effects is presented based on temperature-dependent magnetization curves of superparamagnetic Fe particles. The results show the potential of the approach for adjusting the magnetic properties of nanoparticles, which is essential for application in future data storage media.

Crystal Field Analysis of the Magnetization Curves of HoFe11Ti under High Pressure

2013 ◽  
Vol 818 ◽  
pp. 72-76 ◽  
Author(s):  
Gang Su
Keyword(s):  
High Pressure ◽  
Hydrogen Atom ◽  
Electric Field ◽  
Single Crystals ◽  
High Pressures ◽  
Field Analysis ◽  
Magnetization Curves ◽  
Crystalline Electric Field ◽  
Crystalline Anisotropy ◽  
Magneto Crystalline Anisotropy

The crystalline electric field parameters Anmfor HoFe11Ti under different pressures were evaluated by fitting calculations to the magnetization curves measured on the single crystals at several temperatures. It was found that magneto-crystalline anisotropy has been changed by high pressure and the Anmfor HoFe11Ti under high pressures are strikingly different from Anmfor the corresponding HoFe11Ti H with interstitial hydrogen atom.

Effect of Thickness on Mechanically Tunable Magnetic Anisotropy of FeGa Thin Films Deposited on Flexible Substrates

2015 ◽  
Vol 815 ◽  
pp. 227-232 ◽  
Author(s):  
Ying Yu ◽  
Shu Hong Xie ◽  
Qing Feng Zhan
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Effective Strain ◽  
Anisotropy Field ◽  
Saturation Field ◽  
Effective Anisotropy ◽  
Magnetostriction Constant ◽  
The Difference ◽  
Different Strains

A practical way to manipulate the magnetic anisotropy of magnetostrictive FeGa thin films grown on flexible polyethylene terephthalate (PET) substrates is introduced in this study. The effect of film thickness on magnetic properties and magnetostriction constant of polycrystalline FeGa thin films was investigated. The anisotropy field Hk of flexible FeGa films, i.e., the saturation field determined by fitting the hysteresis curves measured along the hard axis, was enhanced with increasing the tensile strain applied along the easy axis of the thin films, but this enhancement via strain became unconspicuous with increasing the thickness of FeGa films. In order to study the magnetic sensitivity of thin films responding to the external stress, we applied different strains on these films and measure the corresponding anisotropy field. Moreover, the effective magnetostriction constant of FeGa films was calculated from the changes of both anisotropy field and external strain based on the Villari effect. A Neel’s phenomenological model was developed to illustrate that the effective anisotropy field of FeGa thin films was contributed from both the constant volume term and the inverse thickness dependent surface term. Therefore, the magnetic properties for the volume and surface of FeGa thin films were different, which has been verified in this work by using vibrating sample magnetometer (VSM) and magneto-optic Kerr effect (MOKE) system. The anisotropy field contributed by the surface of FeGa film and obtained by MOKE is smaller than that contributed by the film volume and measured by VSM. We ascribed the difference in Hk to the relaxation of the effective strain applied on the films with increasing the thickness of films.

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