Effect of Magnetic and Geometric Properties on the Time of Magnetic Relaxation of Superparamagnetic Core-Shell Nanoparticles

2013 ◽  
Vol 821-822 ◽  
pp. 1336-1340
Author(s):  
Leonid L. Afremov ◽  
Ilia Ilyushin
Keyword(s):  
Relaxation Time ◽  
Magnetic Relaxation ◽  
Superparamagnetic Nanoparticles ◽  
Exchange Constant ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Interphase Interaction ◽  
Geometric Properties ◽  
Core Shell Nanoparticles ◽  
Magnetic States

Within the frame of two-phase superparamagnetic nanoparticles the effect of magnetic and geometric properties of superparamagnetic nanoparicles on the time of their magnetic relaxation has been defined. With increasing of volume, elongation of nanoparticle and relative volume of inclusions the time of relaxation grows rapidly. Metastability conditions of magnetic states have been developed. Growth of exchange constant magnitude of interphase interaction results in increasing of relaxation time regardless of exchange constant sign. Keywords: superparamagnetic particles, core-shell nanoparticles, relaxation time, magnetic states, critical field, metastable magnetic states, interphase exchange interaction.

Influence of Interfacial Exchange Interaction on the Two-Phase Relaxation Time of Superparamagnetic Nanoparticles

2014 ◽  
Vol 893 ◽  
pp. 153-157
Author(s):  
Leonid L. Afremov ◽  
Ilia G. Iliushin
Keyword(s):  
Relaxation Time ◽  
Magnetic Relaxation ◽  
Superparamagnetic Nanoparticles ◽  
Exchange Constant ◽  
Phase Relaxation ◽  
Two Phase ◽  
Interphase Interaction ◽  
Constant Magnitude ◽  
Magnetic States ◽  
Phase Relaxation Time

Within the frame of two-phase superparamagnetic nanoparticles the effect of magnetic and geometric properties of superparamagnetic nanoparicles on the time of their magnetic relaxation has been defined. With increasing of volume the time of relaxation grows rapidly. Metastability conditions of magnetic states have been developed. Growth of exchange constant magnitude of interphase interaction results in increasing of relaxation time regardless of exchange constant sign.

Dependence of Relaxation Time on the Core Size Two-Phase Nanoparticles Magnetite/Titanomagnetite

2015 ◽  
Vol 752-753 ◽  
pp. 418-421
Author(s):  
Ilia Iliushin ◽  
Leonid Afremov ◽  
Sergey Anisimov
Keyword(s):  
Relaxation Time ◽  
Blocking Temperature ◽  
Exchange Constant ◽  
Core Shell ◽  
Core Size ◽  
Shell Nanoparticles ◽  
Two Phase ◽  
The Core ◽  
Core Shell Nanoparticles ◽  
Model Nanoparticles

In this paper, depending of the blocking temperature on magnetite core size for core/shell nanoparticles has been carried out using our theoretical model. Nanoparticles has size of 100nm, and magnetite core increases from 0nm to 100nm. Systems were studied with different values of exchange constant. The data obtained indicate that exchange constant increases the blocking temperature. However, the sign of the constant does not matter.

Magnetic Condition Flat Core/Shell Nanoparticles

2015 ◽  
Vol 752-753 ◽  
pp. 238-242 ◽  
Author(s):  
Leonid Afremov ◽  
Artur Elovskii
Keyword(s):  
Phase Diagrams ◽  
Equilibrium Position ◽  
Magnetic Moments ◽  
Core Shell ◽  
Geometrical Parameters ◽  
Shell Nanoparticles ◽  
Two Phase ◽  
Magnetic Condition ◽  
Core Shell Nanoparticles ◽  
Magnetic States

In terms two-phase nanoparticles model, dependence equilibrium position of magnetic moments of parameters size and elongation nanoparticles core is investigated. Phase diagrams of magnetic states were shown and determine geometrical parameters core, in equilibrium states.

The Preparation and Characteristic of Superparamagnetic Core/Shell Nanoparticles

2013 ◽  
Vol 274 ◽  
pp. 432-435
Author(s):  
Hong Xia Shen ◽  
Zheng Zhi Yin ◽  
Qiong Cheng
Keyword(s):  
Biomedical Applications ◽  
Superparamagnetic Nanoparticles ◽  
Bioactive Molecules ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Vibration Sample Magnetometer ◽  
Diffraction Patterns ◽  
Core Shell Nanoparticles

Superparamagnetic core/shell nanoparticles have been prepared successfully by the reduction of Au3+ onto the surface of superparamagnetic nanoparticles. The core/shell nanoparticles were characterized by Transmission electron microscopy (TEM), X-ray powder diffraction patterns (XRD), UV–vis spectrophotometer, Vibration Sample Magnetometer(VSM) and micro-confocal Raman system. The results revealed that the prepared core/shell nanoparticles were covered by Au shell. These superparamagnetic nanoparticles can be highly sensitively detected and afford new opportunities for biomedical applications through chemical bonding of bioactive molecules with the Au shell of nanoparticles.

scholarly journals Controllable Engineering and Functionalizing Nanoparticles with Specific Targeting Capability

2021 ◽  
Author(s):  
Zhanchen Guo ◽  
Rongrong Xing ◽  
Zhen Liu
Keyword(s):  
Breast Cancer ◽  
Biomedical Applications ◽  
High Specificity ◽  
Superparamagnetic Nanoparticles ◽  
Breast Cancer Cell Lines ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Specific Targeting ◽  
Dual Functional ◽  
Core Shell Nanoparticles

Abstract Due to unique properties, nanoparticles been widely used in important biomedical applications such as imaging, drug delivery and disease therapy. Targeting toward specific proteins is essential for the effective utilization of nanoparticles. However, current targeting strategies mainly rely on surface modification with bio-ligands, which often not only fail to provide desired properties but also remain challenging. Here we report an unprecedented approach, called reverse microemulsion-confined epitope-oriented surface imprinting and cladding (ROSIC), for facile, versatile and controllable engineering coreless and core/shell nanoparticles with tunable monodispersed size as well as specific targeting capability towards proteins and peptides. Via engineering coreless imprinted and cladded silica nanoparticles, the effectiveness and superiority over conventional imprinting of the proposed approach was first verified. The prepared nanoparticles exhibited both high specificity and high affinity. Using quantum dots (QDs), superparamagnetic nanoparticles, silver nanoparticles and upconverting nanoparticles as a representative set of core substrates, a variety of dual-functional single-core/shell nanoparticles were then successfully prepared. Finally, selective fluorescence imaging of triple negative breast cancer cells over other breast cancer cell lines using QD-cored nanoparticles was achieved, which well demonstrated the potential of the prepared core/shell nanoparticles in biomedical applications. Thus, this approach opened a new avenue to engineering and functionalization of advanced nanoparticles with targeting capability, holding great prospects in biomedical applications.

scholarly journals Adjusting the Néel relaxation time of Fe3O4/Zn x Co1−x Fe2O4 core/shell nanoparticles for optimal heat generation in magnetic hyperthermia

2020 ◽  
Vol 32 (6) ◽  
pp. 065703
Author(s):  
Fernando Fabris ◽  
Javier Lohr ◽  
Enio Lima ◽  
Adriele Aparecida de Almeida ◽  
Horacio E Troiani ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Heat Generation ◽  
Magnetic Hyperthermia ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Optimal Heat ◽  
Core Shell Nanoparticles ◽  
Néel Relaxation

scholarly journals The effect of coating of Fe3O4/silica core/shell nanoparticles on T2 relaxation time at 9.4 T

2011 ◽  
Vol 55 (1) ◽  
pp. 10401 ◽  
Author(s):  
B. Blasiak ◽  
Z. Zhang ◽  
X. Zhang ◽  
T. Foniok ◽  
G. R. Sutherland ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Core Shell ◽  
T2 Relaxation Time ◽  
T2 Relaxation ◽  
Shell Nanoparticles ◽  
Silica Core ◽  
Core Shell Nanoparticles

scholarly journals Controlling the dominant magnetic relaxation mechanisms for magnetic hyperthermia in bimagnetic core–shell nanoparticles

Nanoscale ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 3164-3172 ◽  
Author(s):  
Fernando Fabris ◽  
Enio Lima ◽  
Emilio De Biasi ◽  
Horacio E. Troiani ◽  
Marcelo Vásquez Mansilla ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Magnetic Relaxation ◽  
Magnetic Hyperthermia ◽  
Relaxation Mechanism ◽  
Magnetic Saturation ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Effective Magnetic Anisotropy ◽  
Size And Morphology ◽  
Core Shell Nanoparticles

The dominant magnetic relaxation mechanism can be controlled by changing the effective magnetic anisotropy in core/shell nanoparticles, preserving its magnetic saturation, size and morphology for hyperthermia experiments.

Synthesis, Characterization, and Nanocatalysis Application of Core–Shell Superparamagnetic Nanoparticles of Fe3O4@Pd

2015 ◽  
Vol 68 (10) ◽  
pp. 1492 ◽  
Author(s):  
Ariel L. Cappelletti ◽  
Paula M. Uberman ◽  
Sandra E. Martín ◽  
Martín E. Saleta ◽  
Horacio E. Troiani ◽  
...  
Keyword(s):  
Size Distribution ◽  
Good Control ◽  
Superparamagnetic Nanoparticles ◽  
Synthetic Methods ◽  
Core Shell ◽  
Urea Complex ◽  
Scanning Calorimetry ◽  
Shell Nanoparticles ◽  
Palladium Catalyzed ◽  
Core Shell Nanoparticles

There is a wide number of different synthetic methods to obtain magnetite (Fe3O4) superparamagnetic nanoparticles (SPNPs). However, only a few are able to produce very small and well defined SPNPs with narrow size distribution. We report a modification of the metal-complex decomposition in organic media method in which we replace iron(iii) acetylacetonate (Fe(Acac)3) with an iron–urea complex (Fe-Urea) as metal source for the synthesis. With this modification we were able to obtain small particle sizes with a good control in size distribution. The Fe-Urea complex is easy to prepare with excellent yields. Core–shell nanoparticles are then prepared using palladium(ii) acetylacetonate as a Pd source, to obtain a Pd0 shell stabilised by oleylamine. The core–shell superparamagnetic nanoparticles of Fe3O4@Pd-OA are extensively characterized by FT-IR, powder X-ray diffraction, transmission electron microscopy, UV-vis, thermogravimetric analysis/differential scanning calorimetry, and magnetic susceptibility measurements, and tested in a palladium-catalyzed cross-coupling Suzuki–Miyaura reaction with promising results.

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