Intrinsic and Domain Magnetism in Nanocrystalline Materials

Beke, Dezső L.

doi:10.1002/(sici)1521-4079(199810)33:7/8<1039::aid-crat1039>3.0.co;2-x

Cited by 18 publications

(8 citation statements)

References 39 publications

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“…The local magnetic field acting on the i-th nanoparticle was calculated using direct summation. In many papers, the attempt frequency is considered to be f 0 = 10 9 s −1 [32], or to fall within various ranges, such as (10 13 -10 9 ) s −1 [33], and to depend only on the material properties. We considered that the nanoparticle sizes and effective magnetic anisotropy constants had a lognormal distribution, the standard shape deviations were v d d m and v Keff K eff,m , i.e.…”

Section: Resultsmentioning

confidence: 99%

The Néel Magnetic Relaxation Dynamics in Nanoparticle Systems - Phenomenological Approach versus Stochastic Approach

Osaci

2016

Acta Phys. Pol. A

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In nanomagnetism, the studies of magnetic nanoparticle systems are of particular interest from both experimental and theoretical points of view. Experimentally, the measurements made on such a system are hard to interpret. It is very difficult to distinguish the effect of the magnetic dipole interactions from the effects of size distribution or effective magnetic anisotropy constants. In this respect, the simulation models can help. This paper presents a study comparing the two conventional approaches, using simulation models for the magnetic relaxation dynamics of nanoparticle systems, i.e. a phenomenological Ising-type approach, on two levels, and a stochastic approach. The paper also shows a way of using these approaches in creating a model to simulate the Néel magnetic relaxation time for aligned magnetic nanoparticle systems.

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Section: Resultsmentioning

confidence: 99%

The Néel Magnetic Relaxation Dynamics in Nanoparticle Systems - Phenomenological Approach versus Stochastic Approach

Osaci

2016

Acta Phys. Pol. A

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“…It is noted, for example, that the intrinsic magnetic properties of the nanomaterial do not vary considerably with size. The new magnetic behaviour different from their bulk is attributed to their extrinsic properties resulting from their interactions and is strongly dependent on their microstructure [12]. Chemical composition leads to intrinsic properties.…”

Section: Intrinsic Versus Extrinsic Nano-scale Propertiesmentioning

confidence: 99%

Overview of an internationally integrated nanotechnology governance

Devasahayam

2017

Int. J. Metrol. Qual. Eng.

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Abstract. Nanoscience and nanotechnologies (NTs) have huge potential to improve competitiveness and sustainable development across a wide range of industrial sectors. Public perception of NT related to health, safety and environment (HSE) is critical for the responsible development of NT. It warrants a regulatory regime to demonstrate to the general public whether NTs are safe with regard to HSE. This work explores the feasibility of legal metrology (LM) as a platform to address the impact of NT on legal and socio-economic aspects. It considers whether a LM framework needs to be developed for NT and the associated benefits and risks.

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“…The magnetic moments of the i -th and j -th nanoparticle can be indicated with μ i and μ j , respectively, both with uniaxial anisotropy. Since nanoparticle i has a dipole–dipole magnetostatic interaction with all the other nanoparticles, the magnetic dipolar energy of the nanoparticle i and the local dipolar magnetic field acting on the nanoparticle i can be expressed as follows [ 17 – 18 ]:…”

Section: Interacting Colloidal Magnetic Nanoparticlesmentioning

confidence: 99%

An adapted Coffey model for studying susceptibility losses in interacting magnetic nanoparticles

Osaci¹,

Cacciola²

2015

Beilstein J. Nanotechnol.

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Summary Background: Nanoparticles can be used in biomedical applications, such as contrast agents for magnetic resonance imaging, in tumor therapy or against cardiovascular diseases. Single-domain nanoparticles dissipate heat through susceptibility losses in two modes: Néel relaxation and Brownian relaxation. Results: Since a consistent theory for the Néel relaxation time that is applicable to systems of interacting nanoparticles has not yet been developed, we adapted the Coffey theoretical model for the Néel relaxation time in external magnetic fields in order to consider local dipolar magnetic fields. Then, we obtained the effective relaxation time. The effective relaxation time is further used for obtaining values of specific loss power (SLP) through linear response theory (LRT). A comparative analysis between our model and the discrete orientation model, more often used in literature, and a comparison with experimental data from literature have been carried out, in order to choose the optimal magnetic parameters of a nanoparticle system. Conclusion: In this way, we can study effects of the nanoparticle concentration on SLP in an acceptable range of frequencies and amplitudes of external magnetic fields for biomedical applications, especially for tumor therapy by magnetic hyperthermia.

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Intrinsic and Domain Magnetism in Nanocrystalline Materials

Cited by 18 publications

References 39 publications

The Néel Magnetic Relaxation Dynamics in Nanoparticle Systems - Phenomenological Approach versus Stochastic Approach

The Néel Magnetic Relaxation Dynamics in Nanoparticle Systems - Phenomenological Approach versus Stochastic Approach

Overview of an internationally integrated nanotechnology governance

An adapted Coffey model for studying susceptibility losses in interacting magnetic nanoparticles

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