Effective anisotropy constant of polycrystalline nickel ferrite

1961 ◽  
Vol 11 (10) ◽  
pp. 766-768 ◽  
Author(s):  
J. šternberk
Keyword(s):  
Nickel Ferrite ◽  
Anisotropy Constant ◽  
Polycrystalline Nickel ◽  
Effective Anisotropy ◽  
Effective Anisotropy Constant

Magnetic and Microstructural Properties of Cobalt Substituted NiZn Ferrite Powders

2017 ◽  
Vol 265 ◽  
pp. 821-826
Author(s):  
A.V. Knyazev ◽  
E. Lähderanta ◽  
I.A. Zakharchuk
Keyword(s):  
Spinel Structure ◽  
Ionic Radius ◽  
Room Temperature ◽  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Anisotropy Constant ◽  
Microstructural Properties ◽  
Effective Anisotropy ◽  
Good Crystallinity ◽  
Effective Anisotropy Constant

This paper presents the results of magnetic and microstructural study of cobalt-substituted NiZn ferrite powders, Ni0.5Zn0.3Co0.2Fe2O4, synthesized with the solid-state reaction method. The lattice parameter decreased with Co substitution, as the ionic radius of cobalt is less than that of zinc. Raman spectroscopy showed clear peaks of the A1g, Eg, and F2g modes, revealing cubic spinel structure and good crystallinity of the samples. The saturation magnetization reduced in the substituted sample to 50.28 emu/g at room temperature. In comparison to the bulk ferrite, the powder sample showed pronounced coercivity even at room temperature. The temperature dependence of the magnetization had superparamagnetic curvature, which yielded the effective anisotropy constant equal to 8.832 kJ/m3.

Exchange-Coupling Interaction and Effective Anisotropy in Two-Phase Nanocomposite Permanent Magnetic Materials

2005 ◽  
Vol 475-479 ◽  
pp. 2173-2176
Author(s):  
L.M. Liu ◽  
Wei Chen ◽  
M.G. Zhu ◽  
L.Y. Nie ◽  
Ai Jun Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Exchange Coupling ◽  
Coupling Model ◽  
Anisotropy Constant ◽  
Two Phase ◽  
Effective Anisotropy ◽  
Coupling Interaction ◽  
Effective Anisotropy Constant ◽  
Calculation Results ◽  
Exchange Coupling Interaction

Using the part exchange-coupling model, the exchange-coupling interaction between magnetically soft and hard grains in Nd2Fe14B/α-Fe nanocomposite and its effect on the effective anisotropy of the material have been investigated. By testing six different functions, series curves of effective anisotropy constant versus the mean grain size were obtained. The calculation results show that the effective anisotropy of the composite increases slightly with decreasing grain size, reaches the maximum at about 23nm, and then decreases abruptly. The calculated curves resemble the experimental results of the coercivity versus grain size in nanocomposite.

Determination of the effective anisotropy constant of CoFe2O4 nanoparticles through the T-dependence of the coercive field

2016 ◽  
Vol 119 (9) ◽  
pp. 093909 ◽  
Author(s):  
M. H. Carvalho ◽  
R. J. S. Lima ◽  
C. T. Meneses ◽  
W. S. D. Folly ◽  
V. H. V. Sarmento ◽  
...  
Keyword(s):  
Coercive Field ◽  
Anisotropy Constant ◽  
Cofe2o4 Nanoparticles ◽  
Effective Anisotropy ◽  
Effective Anisotropy Constant

Effective Anisotropy Constant of Bilayer Film

2014 ◽  
Vol 887-888 ◽  
pp. 779-782
Author(s):  
Leonid L. Afremov ◽  
Sergey Anisimov ◽  
Tamara Agapova
Keyword(s):  
Magnetic Anisotropy ◽  
Anisotropy Constant ◽  
Second Order ◽  
Bilayer Film ◽  
Effective Anisotropy ◽  
First Order ◽  
Crystallographic Anisotropy ◽  
Effective Anisotropy Constant ◽  
Interlayer Exchange ◽  
Effective Constants

A reasonable composition of different kinds of magnetic anisotropy of bilayer film has been carried out. The criterium of magnetic uniaxiality of bilayer film contained the first-order and the second-order crystallographic anisotropy has been defined. It has been demonstrated that the effective constants of the first-order and the second-order magnetic anisotropy of bilayer film has a non-linear dependence on the corresponding constants of crystallographic anisotropy of the layers, angles between them and constants of interlayer exchange interaction.

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.

scholarly journals Temperature Dependence of Anisotropy in Ti and Gd Doped NiMnGa-Based Multifunctional Ferromagnetic Shape Memory Alloys

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2906
Author(s):  
Amadeusz Łaszcz ◽  
Mariusz Hasiak ◽  
Jerzy Kaleta
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Temperature Dependence ◽  
Magnetocrystalline Anisotropy ◽  
Anisotropy Constant ◽  
Anisotropy Energy ◽  
Ferromagnetic Shape Memory Alloys ◽  
Effective Anisotropy ◽  
Effective Anisotropy Constant ◽  
Ferromagnetic Shape Memory

The temperature dependence of magnetocrystalline anisotropy was investigated in detail for the polycrystalline Ni50Mn25Ga25, Ni50Mn25Ga20Ti5 and Ni50Mn25Ga20Gd5 ferromagnetic shape memory alloys in the temperature range of 50–400 K. The effective anisotropy constant was estimated from a series of high field magnetization curves based on the fitting procedure according to the law of approach to magnetic saturation. The low temperature martensitic phase was found to have a significantly higher anisotropy energy in comparison to a high temperature austenitic phase, which was observed through a sudden, distinct drop of anisotropy energy. The calculated values of the effective anisotropy constant were comparable to the results published by other authors. Moreover, the strong influence of chemical composition on the first-order phase transition and the second-order ferromagnetic to the paramagnetic transition was revealed. Finally, the strong coupling between the temperature dependence of the coercive field and the temperature dependence of magnetocrystalline anisotropy was also shown and discussed in the present study.

Magnetic and Microstructure Study of Thin Films of FeCuNbMoSiB FINEMET Alloy

2016 ◽  
Vol 870 ◽  
pp. 322-327 ◽  
Author(s):  
I.A. Zakharchuk ◽  
E. Mikhalitsyna ◽  
Erkki Lähderanta
Keyword(s):  
Thin Films ◽  
Easy Axis ◽  
Anisotropy Constant ◽  
Effective Anisotropy ◽  
Resistivity Measurements ◽  
Glass Substrates ◽  
Corning Glass ◽  
Post Annealing ◽  
Effective Anisotropy Constant ◽  
The Magnetic Field

Thin films of FeCuNbMoSiB have been sputtered on Corning glass substrates with thicknesses varying from 10 to 200 nm with post annealing at 450 °C and 550 °C. Annealing in the presence of the magnetic field applied along the plane of a substrate develops an uniaxial magnetic anisotropy with the in-plane easy axis. Estimation of the effective anisotropy constant from the magnetization measurements gave Keff = 3.23 kJ/m3. Structure and surface of the films were investigated with the X-ray powder diffraction (XRD), resistivity measurements, and Raman spectroscopy. XRD and resistivity analyses show that thermal annealing at 550 °C improves the crystalline fraction and Fe-Si grain size. Raman spectra identified hematite, goethite, magnetite, as well as graphite contamination of film surfaces.

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