A critical examination of the law of approach to saturation. I. Fit procedure

Größinger, R.

doi:10.1002/pssa.2210660231

Cited by 205 publications

(53 citation statements)

References 20 publications

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“…The term w 0 H becomes more significant when the sample approaches the Curie temperature. However, experimental measurements [99,100] indicated that, in the case of the nanoparticles, a relation of the following form is often sufficient [3,100,101]: …”

Section: Hysteresis Magnetic Behavior Of Nanoparticlesmentioning

confidence: 99%

Nanoparticle Size Effect on Some Magnetic Properties

Caizer

2015

Handbook of Nanoparticles

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Nanoparticles exhibit, from a magnetic point of view, various anomalies and specific magnetic properties, different from those of the bulk with the same chemical composition. Knowing the new magnetic properties is very important, both from theoretical point of view and their numerous practical applications in nanotechnology (nanotechnics and, recently, in nanomedicine), which should be considered. In this chapter we shall present an overview on the following topics: saturation magnetization, magnetic anisotropy, and magnetic behavior of magnetic nanoparticles, in relation with their size and magnetic structure, single-or multi-domains. The magnetic properties of the nanoparticles are compared and discussed in relation to those of the corresponding bulk. The surface effects, in the case of surfacted nanoparticles and those embedded in different matrices, on magnetic properties are presented and discussed in the core-shell model (core of the nanoparticle, where the magnetic moments are aligned under the exchange interaction, and the shell, where the magnetic moments are in a disordered structure).In the case of small (nm to tens of nm), single-domain nanoparticles (without a structure of magnetic domains), their volume is generally smaller than a magnetic domain (Weiss domain), domain in which the magnetic moments from the crystalline network are aligned (ordered) spontaneously at saturation.:This result (Eq. 79) shows that the critical field (coercive field in this case) decreases as the magnetic diameter of the nanoparticles decreases, and becomes zero at the threshold diameter (D m = D mt ). Experimental results broadly confirm the law of variation (Eq. 79) in the range D m =D mt ¼ 1 À 5 ð Þ. Kneller and Luborsky [132] found a good concordance between the calculated and experimental values Handbook of Nanoparticles

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Section: Hysteresis Magnetic Behavior Of Nanoparticlesmentioning

confidence: 99%

Nanoparticle Size Effect on Some Magnetic Properties

Caizer

2015

Handbook of Nanoparticles

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“…So, one have to found some criteria in order to retain only the few pertinent terms involved in the studied case, and for this, different plots have been proposed and rather fully discussed in the past [23,25]. Often, one of the best way is to plot M as function of 1/H because in that case the paraprocess terms make the curve rising up at the low 1/H values (high fields) while the p ¼ À2 term give a negative curvature in the high 1/H range.…”

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High field surface magnetic study of Fe₃O₄ nanoparticles

Kihal

Fillion

Bouzabata

et al. 2011

Physica Status Solidi (b)

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Magnetic properties of magnetite (Fe3O4) powders, milled for various times up to 15 h, are studied by magnetization measurements. For the starting powder, like in the bulk single crystal, the approach to magnetic saturation is mainly ruled by the usual 1/H and 1/H2 terms. But for the milled samples, as the grain size decreases, a 1/H1/2 term rises as the leading term and is interpreted in the framework of the theory of Chudnovsky et al. accounting for the effect of a random anisotropy generated near the surface, aside from a large constant high field susceptibility related to the canted spins at the surface.

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“…The magnetic parameters such as saturation magnetization (M s ), coercivity (H c ), retentivity (M r ) and squareness ratio (M r /M s ) values were obtained from these loops. The values of saturation magnetization (M s ) were calculated by the law of approach (LoA)to saturation[20][21][22] and the fitted curves of M s calculated by this law at different temperatures The following law of approach to saturation was used to obtain the fitted data and this data were fitted by using a least-squares procedure [s is saturation magnetization, A represents the inhomogeneities in the sample, B is proportional to K 2 (K is the anisotropy constant), H is the applied field and χ is the magneticsusceptibility. The saturation magnetization (M s ) and the coercivity (H c ) of the sample were in the range, 49.4-67.9emu/g and 207-1983Oe, respectively, depending on the heat treatment temperature (800 ∼ 1200°C).…”

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confidence: 99%