Size Effects in the Magnetic Properties of ε-Fe2O3 Nanoparticles | Sciact - CRIS-system of Boreskov Institute of Catalysis

Size Effects in the Magnetic Properties of ε-Fe2O3 Nanoparticles Full article

Journal

Journal of Applied Physics
ISSN: 0021-8979 , E-ISSN: 1089-7550

Output data

Year: 2015, Volume: 118, Article number : 213901, Pages count : 12 DOI: 10.1063/1.4936838

Tags

Anisotropy; Crystallography; High resolution electron microscopy; Magnetic anisotropy; Magnetic properties; Magnetic resonance measurement; Magnetic variables measurement; Magnetism; Mossbauer spectroscopy; Nanomagnetics; Nanoparticles; Particle size

Authors

Dubrovskiy A.A. ^1,2 , Balaev D.A. ^1,3 , Shaykhutdinov K.A. ¹ , Bayukov O.A. ¹ , Pletnev O.N. ¹ , Yakushkin S.S. ^4,5 , Bukhtiyarova G.A. ⁴ , Martyanov O.N. ^4,5

Affiliations

1	Kirensky Institute of Physics, Krasnoyarsk 660036, Russia
2	International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-421, Poland
3	Siberian Federal University, Krasnoyarsk 660041, Russia
4	Boreskov Institute of Catalysis, Novosibirsk 630090, Russia
5	Novosibirsk State University, Novosibirsk 630090, Russia

Funding (2)

1	Federal Agency for Scientific Organizations	V.44.1.15.
2	Novosibirsk National Research University

We report the results of comparative analysis of magnetic properties of the systems based on ε-Fe2O3, nanoparticles with different average sizes (from ∼3 to 9 nm) and dispersions. The experimental data for nanoparticles higher than 6–8 nm in size are consistent with the available data, specifically, the transition to the magnetically ordered state occurs at a temperature of ∼500 K and the anomalies of magnetic properties observed in the range of 80–150 K correspond to the magnetic transition. At the same time, Mőssbauer and ferromagnetic resonance spectroscopy data as well as the results of static magnetic measurements show that at room temperature all the investigated samples contain ε-Fe2O3 particles that exhibit the superparamagnetic behavior. It was established that the magnetic properties of nanoparticles significantly change with a decrease in their size to ∼6 nm. According to high-resolution electron microscopy and Mőssbauer spectroscopy data, the particle structure can be attributed to the ε–modification of trivalent iron oxide; meanwhile, the temperature of the magnetic order onset in these particles is increased, the well-known magnetic transition in the range of 80–150 K does not occur, the crystallographic magnetic anisotropy constant is significantly reduced, and the surfacemagnetic anisotropy plays a decisive role. This is apparently due to redistribution of cations over crystallographic positions with decreasing particle size, which was established using Mössbauer spectra. As the particle size is decreased and the fraction of surface atoms is increased, the contribution of an additional magnetic subsystem formed in a shell of particles smaller than ∼4 nm becomes significant, which manifests itself in the static magnetic measurements as paramagnetic contribution.

Dubrovskiy A.A. , Balaev D.A. , Shaykhutdinov K.A. , Bayukov O.A. , Pletnev O.N. , Yakushkin S.S. , Bukhtiyarova G.A. , Martyanov O.N.
Size Effects in the Magnetic Properties of ε-Fe2O3 Nanoparticles
Journal of Applied Physics. 2015. V.118. 213901 :1-12. DOI: 10.1063/1.4936838 WOS Scopus РИНЦ ANCAN OpenAlex

Submitted:	Jul 15, 2015
Accepted:	Nov 18, 2015
Published online:	Dec 1, 2015
Published print:	Dec 7, 2015

Web of science:	WOS:000369918100009
Scopus:	2-s2.0-84949009026
Elibrary:	26734287
Chemical Abstracts:	2015:1935480
Chemical Abstracts (print):	164:65145
OpenAlex:	W2182509619

DB	Citing
Web of science	51
Scopus	55
Elibrary	56
OpenAlex	57