[qmeso-seminar] семинар 10 октября

[Quantum Mesoscopics Dept.]

СЕМИНАР СЕКТОРА КВАНТОВОЙ МЕЗОСКОПИКИ

пятница 10 октября, 15:00, ИТФ



Артём Сбойчаков (ИТПЭ РАН)

High-frequency permeability of a composite with ferromagnetic spherical shells



We study the high-frequency permeability of the composite materials consisting of hollow ferromagnetic
particles embedded into the nonmagnetic media.We model the ferromagnetic particles in composite by spherical
shells: the thickness of the ferromagnetic region d compared to the particles' diameter D can vary in a wide
range, from d << D to d ~ D. We assume that the magnetization distribution in such a particle is nonuniform,
but forms a vortexlike structure: the magnetization is twisted in some plane outside two vortex cores placed at
the poles of the particle. We consider two types of magnetic anisotropy, which help to stabilize such a magnetic
configuration: the easy-plane magnetic anisotropy and the "circular" uniaxial magnetic anisotropy with easy
axis rotated together with the magnetization direction outside the vortex core. The high-frequency permeability
of such a composite material has been studied in the limit of noninteracting particles. We study the dependence
of the permeability on the ratio d/D. We showed that for d ∼ D, the composite's permeability behaves in a
similar manner for both types of magnetic anisotropy. It was also shown that for the second type of magnetic
anisotropy and in the limit d/D << 1, the frequency dependence of the particle's susceptibility is quite similar to
that for the thin film. At the same time, the magnetization oscillations in the ac field are nonhomogeneous for
both types of anisotropy.



[Трансляция: https://zoom.us/j/96948399564?pwd=RXlKbW96Qm1tZEV6SHB0Q2JYeTdrdz09]

подробнее: http://qmeso.itp.ac.ru/seminars.php?abstract=true