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 Магнитная анизотропия игольчатых монокристаллических включений MnSb в матрице InSb

2021 ◽  
Vol 47 (10) ◽  
pp. 46
Author(s):  
А.И. Дмитриев ◽  
А.В. Кочура ◽  
С.Ф. Маренкин ◽  
E. Lahderanta ◽  
А.П. Кузьменко ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Single Crystal ◽  
Saturation Magnetization ◽  
Power Law ◽  
Anisotropy Constant ◽  
Temperature Range

The magnetic anisotropy of needle-like single-crystal MnSb inclusions in the InSb matrix was determined and studied in the temperature range 5 – 350 K. In granular InSb-MnSb samples a power-law dependence of the anisotropy constant K(T) on the saturation magnetization MS(T) is observed in the temperature range 5 – 350 K with an exponent n = 3.2 ± 0.4 in accordance with the theories developed by Akulov, Zener, and Callens.

Temperature Behavior of Magnetization in Multiphase Co-P Powders in Unsaturated Regime

2015 ◽  
Vol 233-234 ◽  
pp. 522-525
Author(s):  
Oksana Anatoljevna Li ◽  
Sergey Viktorovich Komogortsev ◽  
Rauf S. Iskhakov ◽  
Lidia Aleksandrovna Chekanova ◽  
Evgeniy V. Eremin
Keyword(s):  
Magnetic Anisotropy ◽  
Temperature Dependence ◽  
Spontaneous Magnetization ◽  
Anisotropy Constant ◽  
Surprising Result ◽  
Zero Temperature ◽  
Bloch Constant ◽  
Magnetic Anisotropy Constant ◽  
Fitting Parameters ◽  
Good Agreement

In this paper we have proposed a modified expression for the fitting M(T) data in Co-P powders with nanocorundum and nanodiamond precipitates. The expression for M(T) takes into account the effects from both thermal magnetic excitations – Bloch’s T 3/2 law and temperature dependence of the magnetic anisotropy. The fitting parameters are spontaneous magnetization at absolute zero temperature, Bloch constant and order of magnetic anisotropy constant. The obtained Bloch constant is in good agreement with literature data. The order of magnetic anisotropy constant is found to be about 3 that is surprising result and supposedly comes from multiphase nature of the investigated Co-P powder.

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.

Structural, Magnetic and Microwave Absorption Characteristics of Ba1-xLaxFe12O19 (x = 0; 0.1; 0.2;0.3;0.5;0.7)

2020 ◽  
Vol 855 ◽  
pp. 261-267
Author(s):  
Yana Taryana ◽  
Ari Adi Wisnu ◽  
D. Mahmudin ◽  
Yuyu Wahyu ◽  
Azwar Manaf
Keyword(s):  
Microwave Absorption ◽  
Single Phase ◽  
Anisotropy Constant ◽  
Crystalline Anisotropy ◽  
Second Phases ◽  
La Substitution ◽  
Multi Phase ◽  
Magneto Crystalline Anisotropy ◽  
Uniform Particle Size ◽  
Absorption Characteristics

In this study, effect of La substitution on the microstructure, magnetic properties and microwave absorption characteristics of Ba1-xLaxFe12O19 (x=0, 0.1, 0.2, 0.3, 0.5, 0.7) is reported. The samples were synthesized through mechanical alloying and solid reaction a temperature 1200 °C for 2 hours. A single-phase material occurred only at x = 0 and 0.1. Additional second phases were existing in all samples with x ≥ 0.2 which led to multi-phase materials. The single phase (x = 0 and 0.1) has a relatively uniform particle size distribution with a mean crystallite size 138 nm. Additional phases of respectively Fe2O3 and LaFe2O3 were identified in all samples with x ≥ 0.2. Effect of La substitution is to decrease the magneto crystalline anisotropy constant and the saturation magnetization. The latter is due to a decrease in mass fraction of the main magnetic phase. All Ba1-xLaxFe12O19 samples have superior microwave characteristics which able to absorb more than 99 % the incoming electromagnetic wave entering the material. The absorption bandwidth is found relatively wide within the frequency range 8-12 GHz.

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.

On the Calculation of Effective Anisotropy Constant of Nanoparticle

2013 ◽  
Vol 734-737 ◽  
pp. 2310-2313
Author(s):  
Leonid L. Afremov ◽  
Tatyana N. Gnitetskaya ◽  
Elena B. Ivanova
Keyword(s):  
Magnetic Anisotropy ◽  
Temperature Dependence ◽  
Anisotropy Constant ◽  
Shape Anisotropy ◽  
Anisotropy Axis ◽  
Effective Anisotropy ◽  
Effective Constant ◽  
Crystalline Anisotropy ◽  
Effective Anisotropy Constant

A correct composition of two kind of magnetic anisotropy of ellipsoidal nanoparticles: crystalline anisotropy and shape anisotropy - has been carried out. It was shown that according to the shape anisotropy the effective anisotropy constant can change non-monotonically. The temperature dependence of effective anisotropy constant on the angle defining the position of effective axis was calculated. It was found out if the angle between the crystalline anisotropy axis and the long axis of nanoparticle exceedsπ/4, then the effective constant as well as the position of effective axis has to change non-monotonically according to changing of temperature.

Magneto-crystalline anisotropy of NdFe0.9Mn0.1O3 single crystal

2018 ◽  
Vol 536 ◽  
pp. 89-92 ◽  
Author(s):  
Marián Mihalik ◽  
Matúš Mihalik ◽  
Mária Zentková ◽  
Klára Uhlířová ◽  
Marie Kratochvílová ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystalline Anisotropy ◽  
Magneto Crystalline Anisotropy
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