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Registration Number

0220U000582, 0115U004257 , R & D reports

Title

Modeling of the physical properties and development of materials for hard magnetic nanocomposites

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Head

Antonov Viсtor Nikolaevich,

Registration Date

27-04-2020

Organization

G.V. Kyrdyumov Institute for Metall Physics of N.A.S. of Ukraine

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The magnetocrystalline anisotropy energy (MAE) imposes an upper limit on the coercivity of a magnetic system and therefore is of great importance for the development of magnetically hard nanocomposites and permanent magnets. On the basis of modeling in the framework of the density functional theory we have obtained the MAE for the MnBi ferromagnetic system, La1-xPrxCo2P2 phosphides doped with Cr, Mn, Fe, Co, Ni, lithium nitride Li2(Li1-xMx)N doped with Hf, Zr, Ti, Vf, Zr, Ti, Cr, Mn, Fe, Ni, Cu, Zn, systems based on the cerium intermetallide Ce2Co17. Fundamental concepts about the relationship between their electronic structure and physical properties have been developed. It has been shown that the large values of MAE in MnBi are determined by the spin-orbit coupling at Bi as well as the exchange splitting and spin magnetic moments on Mn, and that the temperature dependence of MAE is mainly determined by the lattice thermal expansion in the basal plane. We have found that Li2(Li1-xFex)N with a small concentration of Fe possesses an enormous orbital magnetic moment anisotropy and MAE. The MAE for Li2(Li1-xMx)N (M = Cr, Mn, Co, Ni) is found to be quite large from a point of view of permanent magnetism requirements but at least an order of magnitude smaller than for Li2(Li1-xFex)N. Zr and Hf have been shown to be the most effective dopants to enhance the MAE of Ce2Co17. From the point of view of possible applications it is very desirable to increase the Curie temperature of the investigated systems without losing high magnetic anisotropy. Possible nanocomposites of MnBi, Li2(Li1-xFex)N or Ce2M2Co15 (M = Zr, Hf) with a soft phase having a large Curie temperature (like FeCo) seem promising. Also, the Ce2M2Co15 intermetallides with M = Mn or Fe can be interesting, since these dopants improve the MAE of Ce2M2Co15 preserving the magnetization while other dopants reduce it.

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Бекеньов Лев Валерійович
Зеніна Ірина Борисівна
Ковальчук Галина Іванівна
Кукуста Денис Олександрович
Кучеренко Юрій Миколайович
Мазур Дмитро Вікторович
Мокляк Сергій Вадимович
Сіренко Василь Тихонович
Січкар Сергій Михайлович
Уваров Микола Вікторович

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2020-10-01