Features of the Pulsed Magnetization Switching in a High-Coercivity Material Based on ε-Fe2O3 Nanoparticles
Full article
| Common |
Language:
Английский,
Genre:
Full article,
Status:
Published,
Source type:
Translated
|
| Journal |
Physics of the Solid State
ISSN: 1063-7834
, E-ISSN: 1090-6460
|
| Output data |
Year: 2020,
Volume: 62,
Number: 3,
Pages: 445-453
Pages count
: 9
DOI:
10.1134/S1063783420030166
|
| Tags |
coercivity; dynamic magnetization switching; ε-Fe2O3 nanoparticles |
| Authors |
Popkov S.I.
1
,
Krasikov A.A.
1
,
Semenov S.V.
1
,
Dubrovskii A.A.
1
,
Yakushkin S.S.
2
,
Kirillov V.L.
2
,
Mart’yanov O.N.
2
,
Balaev D.A.
1
|
| Affiliations |
| 1 |
Kirensky Institute of Physics, Krasnoyarsk Scientific Center, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, 660036 Russia
|
| 2 |
Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
|
|
Funding (1)
|
1
|
Russian Foundation for Basic Research
|
18-42-240012 (АААА-А18-118102390052-8)
|
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. © 2020, Pleiades Publishing, Ltd.