Superferromagnetism in chain-like $Fe@SiO_2$ nanoparticle ensembles

Zeleňáková, A.; Hrubovčák, P.; Strečková, M.; Matko, I.; Zeleňák, V.; Kováč, J.

doi:10.1063/1.4890354

Journal Article

DESY-2014-03389

Superferromagnetism in chain-like $Fe@SiO_2$ nanoparticle ensembles

Zeleňáková, A. (Corresponding Author)Extern* ; Zeleňák, V.Extern* ; Matko, I. ; Strečková, M. ; Hrubovčák, P.Extern* ; Kováč, J.

2014
American Institute of Physics Melville, NY

Journal of applied physics 116(3), 033907 (2014) [10.1063/1.4890354]

This record in other databases:

Please use a persistent id in citations: doi:10.1063/1.4890354

Abstract: One-dimensional (1D) chain-like nanocomposites, created by ensembles of nanoparticles of with diameter ∼ 13 nm, which are composed of an iron core (∼4 nm) and a silica protective layer, were prepared by a self-assembly process. Chain-like Fe@SiO2 ensembles were formed due to strong magnetic dipole–dipole interactions between individual Fe nanoparticles and the subsequent fixation of the Fe particles by the SiO2 layers. X-ray near edge absorption spectra measurements at the Fe K absorption edge confirm that the presence of a silica layer prevents the oxidation of the magnetic Fe core. Strong magnetic interactions between Fe cores lead to long-range ordering of magnetic moments, and the nanoparticle ensembles exhibit superferromagnetic characteristics demonstrated by a broad blocking Zero-field cooling (ZFC)/field-cooling distribution, nearly constant temperature dependence of ZFC magnetization, and non-zero coercivity at room temperature. Low room-temperature coercivity and the presence of electrically insulating SiO2 shells surrounding the Fe core make the studied samples suitable candidates for microelectronic applications.

Classification: