Mean-field modelling of magnetic nanoparticles: The effect of particle size and shape on the Curie temperature

Penny, Charles; Muxworthy, Adrian R.; Fabian, Karl

doi:10.1103/physrevb.99.174414

Cited by 14 publications

(8 citation statements)

References 28 publications

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“…We start with a nucleation diameter for magnetite of 2 nm (Baumgartner et al., 2013). For particles greater than a few nanometers, M s is independent of v (Penny et al., 2019). This is much below the blocking volume of the minerals of interest, therefore we assume M s to be independent of v .…”

Section: Methodsmentioning

confidence: 99%

Using Preisach Theory to Evaluate Chemical Remanent Magnetization and Its Behavior During Thellier‐Thellier‐Coe Paleointensity Experiments

Baker

Muxworthy

2023

JGR Solid Earth

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Magnetic minerals within rocks, meteorites and sediments can record the ambient magnetic field during their formation, acquiring remanent magnetizations. There are several recording mechanisms depending on the rock type and mineral formation. For example, a thermoremanent magnetization (TRM) is acquired during cooling from above the constituent minerals' Curie temperatures, and chemical remanent magnetizations (CRM) are acquired if a mineral forms or alters below its Curie temperature. The recording mechanisms of these various remamances differs. Whilst much attention has historically been given to TRM acquisition (e.g.,

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Section: Methodsmentioning

confidence: 99%

Using Preisach Theory to Evaluate Chemical Remanent Magnetization and Its Behavior During Thellier‐Thellier‐Coe Paleointensity Experiments

Baker

Muxworthy

2023

JGR Solid Earth

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“…Penny et al [20] have shown that a mean-field approach is valuable for the investigation of finite-size effects, including lattice types and particle shapes. To support the interpretation of our atomistic model calculation, we use a lattice site resolved Mean-field model outlined as follows [21].…”

Section: B Lattice Site Resolved Mean-field Modelmentioning

confidence: 99%

Influence of the Finite-size Effects on the Curie Temperature of L10-FePt

Nguyen¹,

Ruta²,

Hovorka³

et al. 2022

Preprint

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We employ an atomistic model using a nearest-neighbor Heisenberg Hamiltonian exchange to study computationally the dependence of the Curie temperature of L1 0 -FePt on finite-size and surface effects in Heat-assisted Magnetic Recording (HAMR) media. We demonstrate the existence of a size threshold at 3.5nm below which the impact of finite-size effects start to permeate into the center of the grains and contribute to the reduction of the Curie temperature. We find a correlation between the Curie temperature and the percentage of atomistic bonds lost on the surface as a function of grain size, which can be extended to apply to not only L1 0 -FePt but also generic magnetic systems of any crystal structure. The investigation gives insight into finite-size effects which, because the inevitable grain size dispersion leads to an irreducible contribution to a dispersion of the Curie temperature, has been predicted to be a serious limitation of HAMR.

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“…Penny et al [21] have shown that a mean-field approach is valuable for the investigation of finite-size effects, including lattice types and particle shapes. To support the interpretation of our atomistic model calculation, we use a lattice site resolved mean-field model outlined as follows [22].…”

Section: B Lattice Site Resolved Mean-field Modelmentioning

confidence: 99%

Influence of finite-size effects on the Curie temperature ofL10−FePt

et al. 2022

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We employ an atomistic model using a nearest-neighbor Heisenberg Hamiltonian exchange to study computationally the dependence of the Curie temperature of L1 0 -FePt on finite-size and surface effects in heat-assisted magnetic recording (HAMR) media. We demonstrate the existence of a size threshold at 3.5 nm below which the impact of finite-size effects starts to permeate into the center of the grains and contributes to the reduction of the Curie temperature. We find a correlation between the Curie temperature and the percentage of atomistic bonds lost on the surface as a function of grain size, which can be extended to apply to not only L1 0 -FePt but also generic magnetic systems of any crystal structure. In a recording medium, the inevitable grain size dispersion leads to an irreducible contribution to the dispersion of the Curie temperature. Therefore, our paper gives insight into finite-size effects, which have been predicted to be a serious limitation of HAMR.

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Mean-field modelling of magnetic nanoparticles: The effect of particle size and shape on the Curie temperature

Cited by 14 publications

References 28 publications

Using Preisach Theory to Evaluate Chemical Remanent Magnetization and Its Behavior During Thellier‐Thellier‐Coe Paleointensity Experiments

Using Preisach Theory to Evaluate Chemical Remanent Magnetization and Its Behavior During Thellier‐Thellier‐Coe Paleointensity Experiments

Influence of the Finite-size Effects on the Curie Temperature of L10-FePt

Influence of finite-size effects on the Curie temperature ofL10−FePt

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