Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/103050
Title: Exchange-bias and magnetic anisotropy fields in core–shell ferrite nanoparticles
Authors: Silva, F. G.
Depeyrot, J.
Raikher, Y. L.
Stepanov, V. I.
Poperechny, I. S.
Aquino, R.
Ballon, G.
Geshev, J.
Dubois, E.
Perzynski, R.
Issue Date: 2021
Publisher: Nature Research
Citation: Exchange-bias and magnetic anisotropy fields in core–shell ferrite nanoparticles / F. G. Silva, J. Depeyrot, Y. L. Raikher, et al. — DOI 10.1038/s41598-021-84843-0 // Scientific Reports. — 2021. — Vol. 11. — Iss. 1. — 5474.
Abstract: Exchange bias properties of MnFe2O4@γ–Fe2O3 core–shell nanoparticles are investigated. The measured field and temperature dependencies of the magnetization point out a well-ordered ferrimagnetic core surrounded by a layer with spin glass-like arrangement. Quasi-static SQUID magnetization measurements are presented along with high-amplitude pulse ones and are cross-analyzed by comparison against ferromagnetic resonance experiments at 9 GHz. These measurements allow one to discern three types of magnetic anisotropies affecting the dynamics of the magnetic moment of the well-ordered ferrimagnetic NP’s core viz. the easy-axis (uniaxial) anisotropy, the unidirectional exchange-bias anisotropy and the rotatable anisotropy. The uniaxial anisotropy originates from the structural core–shell interface. The unidirectional exchange-bias anisotropy is associated with the spin-coupling at the ferrimagnetic/spin glass-like interface; it is observable only at low temperatures after a field-cooling process. The rotatable anisotropy is caused by partially-pinned spins at the core/shell interface; it manifests itself as an intrinsic field always parallel to the external applied magnetic field. The whole set of experimental results is interpreted in the framework of superparamagnetic theory, i.e., essentially taking into account the effect of thermal fluctuations on the magnetic moment of the particle core. In particular, it is found that the rotatable anisotropy of our system is of a uniaxial type. © 2021, The Author(s).
URI: http://hdl.handle.net/10995/103050
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85102294166
PURE ID: 21018012
40b4c8fc-2786-4f04-950b-7f78efdd742b
ISSN: 20452322
DOI: 10.1038/s41598-021-84843-0
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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