Beating the limitation of the Néel temperature of FeO with antiferromagnetic proximity in FeO/CoO

Kozioł–Rachwał, A.; Szpytma, M.; Spiridis, N.; Freindl, K.; Korecki, J.; Janus, W.; Nayyef, H.; Dróżdż, P.; Ślęzak, M.; Zając, M.; Ślęzak, T.

doi:10.1063/5.0082729

Cited by 3 publications

(2 citation statements)

References 41 publications

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“…The direction of the incoming X-rays is parallel to the sample normal and its linear polarization is parallel either to the Fe [1][2][3][4][5][6][7][8][9][10] or to Fe[001] in-plane direction including material science, surface physics, magnetism, and biological systems. The most successful projects were focused on charge storage materials related to Li-or Na-based batteries [6], superconductors [7], and magnetism of the multilayer systems [8][9][10][11][12][13]. In Fig.…”

Section: Present Status and Scientific Highlightsmentioning

confidence: 99%

SOLARIS National Synchrotron Radiation Centre in Krakow, Poland

et al. 2023

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The SOLARIS synchrotron located in Krakow, Poland, is a third-generation light source operating at medium electron energy. The first synchrotron light was observed in 2015, and the consequent development of infrastructure lead to the first users’ experiments at soft X-ray energies in 2018. Presently, SOLARIS expands its operation towards hard X-rays with continuous developments of the beamlines and concurrent infrastructure. In the following, we will summarize the SOLARIS synchrotron design, and describe the beamlines and research infrastructure together with the main performance parameters, upgrade, and development plans.

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Section: Present Status and Scientific Highlightsmentioning

confidence: 99%

SOLARIS National Synchrotron Radiation Centre in Krakow, Poland

et al. 2023

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“…Moreover, using the substitution, the compressive deformations lead to a decrease of the distances between the localized spins and an increase of the super-exchange interaction constant J between them, which naturally leads to an increase of

. It must be noted that

has also a maximum, because FeO and CoO are antiferromagnetic with a Neel temperature of

= 198 K and 291 K, respectively, (not considered here) [ 52 ].…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

Magnetic, Optical and Phonon Properties of Ion-Doped MgO Nanoparticles. Application for Magnetic Hyperthermia

2023

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The influence of size and doping effects on the magnetization M, phonon ω and band gap energy Eg of MgO nanoparticles is studied using a microscopic model. The room-temperature ferromagnetism is due to surface or/and doping effects in MgO nanoparticles (NPs). The influence of the spin–phonon interaction is discussed. M increases with decreasing NP size. M and Eg can increase or decrease by different ion doping (Co, Al, La, Fe) due to the different strain that appears. It changes the lattice parameters and the exchange interaction constants. We found that MgO NP with size of 20 nm and Fe- or Co-doping concentration x = 0.1 and x = 0.2, respectively, have a Curie temperature TC = 315 K, i.e., they are appropriate for application in magnetic hyperthermia, they satisfy the conditions for that. The energy of the phonon mode ω = 448 cm−1 increases with decreasing NP size. It increases with increasing Co and Fe, or decreases with Sr ion doping.

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Enhancing Crystallinity and Magnetic Properties of Cobalt Ferrite Nanoparticles via Thermal Oxidation

Poon,

Singh

2024

ChemNanoMat

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Cobalt ferrite (CFO) nanoparticles (NPs) are highly promising for data storage, energy conversion, permanent magnets, and biomedical applications owing to their exceptional magnetic properties. However, the presence of phase impurities (particularly FeO and CoO) can severely degrade their magnetic properties, hindering their practical use. Here, we present a simple post‐synthesis oxidation approach to address this challenge. Our method involves the thermal decomposition of Fe‐Co oleate followed by oxidation using trimethylamine N‐oxide. The results reveal the effective elimination of FeO and CoO impurities and the formation of spinel ferrite crystal structures post‐oxidation with no change in morphology or size. Magnetic measurements demonstrate a significant enhancement in magnetic properties (e.g., magnetic saturation, coercivity, and blocking temperature) in oxidized CFO NPs compared to the non‐oxidized counterparts, indicative of the recovered ferrimagnetic structure upon post‐synthesis oxidation. As expected, the restoration of the ferrimagnetic structure, resulting in improved magnetic anisotropy, led to decreased SAR values as the nanoparticles moved away from the optimal anisotropy range. The study underscores the necessity of post‐synthesis oxidation for ensuring phase purity and enhancing the magnetic properties of CFO NPs, irrespective of the synthesis method. This approach offers a promising route for producing highly functional magnetic nanoparticles for practical applications.

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Beating the limitation of the Néel temperature of FeO with antiferromagnetic proximity in FeO/CoO

Cited by 3 publications

References 41 publications

SOLARIS National Synchrotron Radiation Centre in Krakow, Poland

SOLARIS National Synchrotron Radiation Centre in Krakow, Poland

Magnetic, Optical and Phonon Properties of Ion-Doped MgO Nanoparticles. Application for Magnetic Hyperthermia

Enhancing Crystallinity and Magnetic Properties of Cobalt Ferrite Nanoparticles via Thermal Oxidation

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