/ S. I. Popkov, A. A. Krasikov, S. V. Semenov [et al.]> // Phys. Solid State. - 2020. -
Vol. 62,
Is. 3. - P. 445-453,
DOI 10.1134/S1063783420030166. - Cited References: 44. - The study was supported by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Krai, and the Krasnoyarsk Territorial Foundation for Support of Scientific and R&D Activities, project no. 18-42-240012 "Magnetization Switching of Magnetic
Nanoparticles in Strong Pulsed Magnetic Fields: New Approach to Studying the Dynamic Effects Related to the Magnetization of Magnetic
Nanoparticles."
. - ISSN 1063-7834. - ISSN 1090-6460
РУБ Physics, Condensed Matter
Аннотация: The magnetic structure of the ε-Fe2O3 iron oxide polymorphic modification is collinear ferrimagnetic in the range from room temperature to ~150 K. As the temperature decreases, ε-Fe2O3 undergoes a magnetic transition accompanied by a significant decrease in the coercivity Hc and, in the low-temperature range, the compound has a complex incommensurate magnetic structure. We experimentally investigated the dynamic magnetization switching of the ε-Fe2O3
nanoparticles with an average size of 8 nm in the temperature range of 80–300 K, which covers different types of the magnetic structure of this iron oxide. A bulk material consisting of xerogel SiO2 with the ε-Fe2O3
nanoparticles embedded in its pores was examined. The magnetic hysteresis loops under dynamic magnetization switching were measured using pulsed magnetic fields Hmax of up to 130 kOe by discharging a capacitor bank through a solenoid. The coercivity Нс upon the dynamic magnetization switching noticeably exceeds the Нс value under the quasi-static conditions. This is caused by the superparamagnetic relaxation of magnetic moments of particles upon the pulsed magnetization switching. In the range from room temperature to ~ 150 K, the external field variation rate dH/dt is the main parameter that determines the behavior of the coercivity under the dynamic magnetization switching. It is the behavior that is expected for a system of single-domain ferro- and ferrimagnetic particles. Under external conditions (at a temperature of 80 K) when the ε-Fe2O3 magnetic structure is incommensurate, the coercivity during the pulsed magnetization switching depends already on the parameter dH/dt and is determined, to a great extent, by the maximum applied field Hmax. Such a behavior atypical of systems of ferrimagnetic particles is caused already by the dynamic spin processes inside the ε-Fe2O3 particles during fast magnetization switching.
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Держатели документа: Russian Acad Sci, Kirensky Inst Phys, Krasnoyarsk Sci Ctr, Siberian Branch, Krasnoyarsk 660036, Russia.
Russian Acad Sci, Boreskov Inst Catalysis, Siberian Branch, Novosibirsk 630090, Russia.
Доп.точки доступа: Popkov, S. I.; Попков, Сергей Иванович; Krasikov, A. A.; Красиков, Александр Александрович; Semenov, S. V.; Семёнов, Сергей Васильевич; Dubrovskii, A. A.; Дубровский, Андрей Александрович; Yakushkin, S. S.; Kirillov, V. L.; Mart'yanov, O. N.; Balaev, D. A.; Балаев, Дмитрий Александрович; Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR); Government of the Krasnoyarsk Krai; Krasnoyarsk Territorial Foundation [18-42-240012]