Room Temperature Blocked Magnetic Nanoparticles Based on Ferrite Promoted by a Three-Step Thermal Decomposition Process

Sartori, Kevin; Choueikani, Fadi; Gloter, Alexandre; Bégin‐Colin, Sylvie; Taverna, Dario; Pichon, Benoît P.

doi:10.1021/jacs.9b03965

Cited by 38 publications

(42 citation statements)

References 26 publications

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“…Furthermore, it may also partially account from the high content of Fe 2+ . 39 These results confirm those of Lopez-Ortega et al 52 who reported cell parameters of 8.40-8.42 Å for Co0.6-0.7Fe2.4-2.3O4 nanoparticles of different sizes.…”

Section: Resultssupporting

confidence: 90%

A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic Fe_3−δO₄@CoFe₂O₄@Fe_3−δO₄ Nanoparticles

Sartori

Musat

Choueikani

et al. 2021

ACS Appl. Mater. Interfaces

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Nanoparticles which combine several magnetic phases offer wide perspectives for cutting edge applications because of the high modularity of their magnetic properties. Besides the addition of the magnetic characteristics intrinsic to each phase, the interface that results from core-shell and, further, from onion structures leads to synergistic properties such as magnetic exchange coupling. Such a phenomenon is of high interest to overcome the superparamagnetic limit of iron oxide nanoparticles which hampers potential applications such as data storage or sensors. In this manuscript, we report on the design of nanoparticles with an onion-like structure which have been scarcely reported yet. These nanoparticles consist in a Fe3- O4 core covered by a first shell of CoFe2O4 and a second shell of Fe3- O4, e.g. a Fe3- O4@CoFe2O4@Fe3- O4 onion-like structure. They were synthesized by a multi-step seed mediated growth approach which consists to perform three successive thermal decomposition of a metal complexes in a high boiling point solvent (about 300 °C). Although TEM micrographs clearly show the growth of each shell from the iron oxide core, core sizes and shell thicknesses markedly differ from what is suggested by the size increase. We investigated very precisely the structure of nanoparticles in performing high resolution (scanning) TEM imaging and geometrical phase analysis (GPA). The chemical composition and spatial distribution of atoms were studied by electron energy loss spectroscopy (EELS) mapping and spectroscopy. The chemical environment and oxidation state of cations were investigated by Mössbauer spectrometry, soft X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD). The combination of these techniques allowed us to estimate the increase of Fe 2+ content in the iron oxide core of the core@shell structure and the increase of the cobalt ferrite shell thickness in the core@shell@shell one, while the iron oxide shell appears to be much thinner than expected. Thus, the modification of the chemical composition as well as the size of the Fe3- O4 core and the thickness of the cobalt ferrite shell have a high impact on the magnetic properties. Furthermore, the growth of the iron oxide shell also markedly modifies the magnetic properties of the core-shell nanoparticles, thus demonstrating the high potential of onion-like nanoparticles for tuning accurately the magnetic properties of nanoparticles according to the desired applications.

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Section: Resultssupporting

confidence: 90%

A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic Fe_3−δO₄@CoFe₂O₄@Fe_3−δO₄ Nanoparticles

Sartori

Musat

Choueikani

et al. 2021

ACS Appl. Mater. Interfaces

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“…The interface exchange coupling in core/shell NPs provides an additional degree of freedom to control the magnetic properties of nanostructures 37,39,55 and can be exploited, for example, to enhance the anisotropy energy avoiding an undesired increase in the NP size. 56 Therefore, our next step was to identify to what extent our system would allow for control over the magnetic moment and anisotropy by performing dc magnetometry experiments, which are summarized in Figure 3 and Figure S4. The lowtemperature curves shown in Figure 3a indicate a single reversal process for all samples.…”

Section: Resultsmentioning

confidence: 99%

Origin and Shell-Driven Optimization of the Heating Power in Core/Shell Bimagnetic Nanoparticles

Lavorato

Das

Xing

et al. 2020

ACS Appl. Nano Mater.

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The magnetic properties of core/shell nanoparticles can be finely tuned through the exchange coupling at the interface, enabling large heating powers under alternating magnetic fields. However, the origin of their heating efficiency is still unclear due to the complex interplay of different heating mechanisms. Here, we show that monodisperse Fe 3 O 4 /Co x Zn 1−x Fe 2 O 4 core/shell nanoparticles can be designed to provide large heating powers for different field amplitudes and dispersion media conditions by modulating their shell composition and thickness. The fine control of the nanoparticles' effective anisotropy provided by the interface coupling between core and shell leads to values up to ∼2400 W g −1 for water colloids and ∼1000 W g −1 for immobilized particles at 80 mT and 309 kHz. A reduction in the shell thickness or Co/Zn ratio results in a transition from a viscous heating regime to a region governed by a collective behavior, characterized by chainlike formation due to interparticle interactions. These results shed light on the origin of the large heating powers of core/shell ferrites and provide an empirical guide to design highly efficient magnetic nanoheaters.

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“…Hard–soft exchange couplings at Fe 3 O 4 ‐Co doped ferrite and Co‐doped ferrite‐Fe 3 O 4 interfaces largely influenced the superparamagnetic blocking temperature and magnetization hysteresis loops. [ 163 ] Despite being a promising approach, one has to bear in mind that synthesis of multi layered nanoparticles is much more challenging than those iron oxide nanoparticles formed via one‐pot reactions.…”

Section: Defect‐engineering In Iron Oxide Nanoparticlesmentioning

confidence: 99%

“…Recently, trimagnetic Fe3O4-CoO-Fe3O4 core-shell-shell nanoparticles have been developed via seed-mediated thermal decomposition synthesis. Hard-soft exchange couplings at Fe3O4-Co doped ferrite and Co-doped ferrite-Fe3O4 interfaces largely influenced the superparamagnetic blocking temperature and magnetization hysteresis loops [148] .…”

Section: Structural Defects Associated With Interfaces and Dopingmentioning

confidence: 99%

Embracing Defects and Disorder in Magnetic Nanoparticles

2021

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Iron oxide nanoparticles have tremendous scientific and technological potential in a broad range of technologies, from energy applications to biomedicine. To improve their performance, single‐crystalline and defect‐free nanoparticles have thus far been aspired. However, in several recent studies, defect‐rich nanoparticles outperform their defect‐free counterparts in magnetic hyperthermia and magnetic particle imaging (MPI). Here, an overview on the state‐of‐the‐art of design and characterization of defects and resulting spin disorder in magnetic nanoparticles is presented with a focus on iron oxide nanoparticles. The beneficial impact of defects and disorder on intracellular magnetic hyperthermia performance of magnetic nanoparticles for drug delivery and cancer therapy is emphasized. Defect‐engineering in iron oxide nanoparticles emerges to become an alternative approach to tailor their magnetic properties for biomedicine, as it is already common practice in established systems such as semiconductors and emerging fields including perovskite solar cells. Finally, perspectives and thoughts are given on how to deliberately induce defects in iron oxide nanoparticles and their potential implications for magnetic tracers to monitor cell therapy and immunotherapy by MPI.

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Room Temperature Blocked Magnetic Nanoparticles Based on Ferrite Promoted by a Three-Step Thermal Decomposition Process

Cited by 38 publications

References 26 publications

A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic Fe_3−δO₄@CoFe₂O₄@Fe_3−δO₄ Nanoparticles

A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic Fe_3−δO₄@CoFe₂O₄@Fe_3−δO₄ Nanoparticles

Origin and Shell-Driven Optimization of the Heating Power in Core/Shell Bimagnetic Nanoparticles

Embracing Defects and Disorder in Magnetic Nanoparticles

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Room Temperature Blocked Magnetic Nanoparticles Based on Ferrite Promoted by a Three-Step Thermal Decomposition Process

Cited by 38 publications

References 26 publications

A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic Fe3−δO4@CoFe2O4@Fe3−δO4 Nanoparticles

A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic Fe3−δO4@CoFe2O4@Fe3−δO4 Nanoparticles

Origin and Shell-Driven Optimization of the Heating Power in Core/Shell Bimagnetic Nanoparticles

Embracing Defects and Disorder in Magnetic Nanoparticles

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A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic Fe_3−δO₄@CoFe₂O₄@Fe_3−δO₄ Nanoparticles

A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic Fe_3−δO₄@CoFe₂O₄@Fe_3−δO₄ Nanoparticles