Magnetic Properties of Bi-Magnetic Core/Shell Nanoparticles: The Case of Thin Shells

Omelyanchik, Alexander; Villa, Silvia; Singh, Gurvinder; Rodionova, Valeria; Laureti, S.; Canepa, F.; Peddis, Davide

doi:10.3390/magnetochemistry7110146

Cited by 6 publications

(2 citation statements)

References 51 publications

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“…Nanocrystalline magnetic SCs are of interest both for fundamental problems of condensed matter physics and for practical applications, due to the appearance of new properties, when the particle size of a SC is reduced to the nanometer scale [112][113][114]. For the past decade the development of magnetic materials, particularly manganites and ferrites in nano-form, has undergone a fast evolutionary growth as strategic materials in spintronics and sensor applications [115][116][117][118].…”

Section: Nanocrystalline Magnetic Semiconductors-new Functional Mater...mentioning

confidence: 99%

Magnetic Semiconductors as Materials for Spintronics

Telegin

Sukhorukov

2022

Magnetochemistry

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From the various aspects of spintronics the review highlights the area devoted to the creation of new functional materials based on magnetic semiconductors and demonstrates both the main physical phenomena involved and the technical possibilities of creating various devices: maser, p-n diode with colossal magnetoresistance, spin valve, magnetic lens, optical modulators, spin wave amplifier, etc. Particular attention is paid to promising research directions such as ultrafast spin transport and THz spectroscopy of magnetic semiconductors. Special care has been taken to include a brief theoretical background and experimental results for the new spintronics approach employing magnetostrictive semiconductors—strain-magnetooptics. Finally, it presents top-down approaches for magnetic semiconductors. The mechano-physical methods of obtaining and features of the physical properties of high-density nanoceramics based on complex magnetic oxides are considered. The potential possibility of using these nanoceramics as an absorber of solar energy, as well as in modulators of electromagnetic radiation, is shown.

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Section: Nanocrystalline Magnetic Semiconductors-new Functional Mater...mentioning

confidence: 99%

Magnetic Semiconductors as Materials for Spintronics

Telegin

Sukhorukov

2022

Magnetochemistry

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“…Magnetic properties, such as saturation magnetization, exchange bias, and coercivity of coupled bi-magnetic nanoparticles, are greatly influenced by the thickness and nature of the interface phases. The most often investigated systems for exchange bias are with antiferromagnetic/ferromagnetic and antiferromagnetic/ferrimagnetic interfaces [ 6 , 7 ]. The exchange bias effect is predicted to cause improved efficiency in magnetothermal conversion due to the magnetic interface effect caused by the individual phases [ 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Hyperthermia of Magnetically Soft-Soft Core-Shell Ferrite Nanoparticles

Narayanaswamy

Jagal

Khurshid

et al. 2022

IJMS

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Magnetically soft-soft MnFe2O4-Fe3O4 core-shell nanoparticles were synthesized through a seed-mediated method using the organometallic decomposition of metal acetyl acetonates. Two sets of core-shell nanoparticles (S1 and S2) of similar core sizes of 5.0 nm and different shell thicknesses (4.1 nm for S1 and 5.7 nm for S2) were obtained by changing the number of nucleating sites. Magnetic measurements were conducted on the nanoparticles at low and room temperatures to study the shell thickness and temperature dependence of the magnetic properties. Interestingly, both core-shell nanoparticles showed similar saturation magnetization, revealing the ineffective role of the shell thickness. In addition, the coercivity in both samples displayed similar temperature dependencies and magnitudes. Signatures of spin glass (SG) like behavior were observed from the field-cooled temperature-dependent magnetization measurements. It was suggested to be due to interface spin freezing. We observed a slight and non-monotonic temperature-dependent exchange bias in both samples with slightly higher values for S2. The effective magnetic anisotropy constant was calculated to be slightly larger in S2 than that in S1. The magnetothermal efficiency of the chitosan-coated nanoparticles was determined by measuring the specific absorption rate (SAR) under an alternating magnetic field (AMF) at 200–350 G field strengths and frequencies (495.25–167.30 kHz). The S2 nanoparticles displayed larger SAR values than the S1 nanoparticles at all field parameters. A maximum SAR value of 356.5 W/g was obtained for S2 at 495.25 kHz and 350 G for the 1 mg/mL nanoparticle concentration of ferrogel. We attributed this behavior to the larger interface SG regions in S2, which mediated the interaction between the core and shell and thus provided indirect exchange coupling between the core and shell phases. The SAR values of the core-shell nanoparticles roughly agreed with the predictions of the linear response theory. The concentration of the nanoparticles was found to affect heat conversion to a great extent. The in vitro treatment of the MDA-MB-231 human breast cancer cell line and HT-29 human colorectal cancer cell was conducted at selected frequencies and field strengths to evaluate the efficiency of the nanoparticles in killing cancer cells. The cellular cytotoxicity was estimated using flow cytometry and an MTT assay at 0 and 24 h after treatment with the AMF. The cells subjected to a 45 min treatment of the AMF (384.50 kHz and 350 G) showed a remarkable decrease in cell viability. The enhanced SAR values of the core-shell nanoparticles compared to the seeds with the most enhancement in S2 is an indication of the potential for tailoring nanoparticle structures and hence their magnetic properties for effective heat generation.

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Characterization of Core–Shell CaFe1.925Sm0.05Gd0.025O4 @ Polymer from Synthesis to Applications

Ateia

Saeid

2023

J Inorg Organomet Polym

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A novel core/shell nanoferrite material has been developed for use in various potential applications. Rare-earth doped calcium-ferrite with the compositional formula $$\text{Ca}{\text{Fe}}_{1.925}{\text{Sm}}_{0.05}{\text{Gd}}_{0.025}{\text O}_4$$ CaFe 1.925 Sm 0.05 Gd 0.025 O 4 was prepared as a core using the citrate auto-combustion method before being coated with PVA as a polymeric shell. High crystalline and single-phase orthorhombic nanoparticles are confirmed by XR-D (X-ray diffraction). An estimate has been made for the mean size of the crystal structures by analyzing the broadening of XR-D lines within a range of 20 nanometers. HR-TEM (high-resolution tunnelling electron microscope) micrographs also showed that the particles had an orthorhombic shape with well-defined boundaries. EDX (energy-dispersive X-ray) and FT-IR were used to investigate the elemental constitution and the molecular structure of samples. The dielectric properties were discussed in the basics of interfacial polarization and Koop`s model. The anti-ferromagnetic nature of the samples was identified by a VSM (vibrating sample magnetometer). The proposed composition was found to improve the electromagnetic absorption performance, which was confirmed with the measurements of optical parameters from the absorbance spectrum recorded by the UV–VIS–NIR spectroscope. The optical band-gap and Urbach energies of the synthesized samples have been investigated, in addition to the refractive index and the extinction coefficient. The Wemple-DiDomenico oscillator model was used to examine the dispersion energies.

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Magnetic Properties of Bi-Magnetic Core/Shell Nanoparticles: The Case of Thin Shells

Cited by 6 publications

References 51 publications

Magnetic Semiconductors as Materials for Spintronics

Magnetic Semiconductors as Materials for Spintronics

Hyperthermia of Magnetically Soft-Soft Core-Shell Ferrite Nanoparticles

Characterization of Core–Shell CaFe1.925Sm0.05Gd0.025O4 @ Polymer from Synthesis to Applications

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