Dipolar Interaction and Sample Shape Effects on the Hysteresis Properties of 2d Array of Magnetic Nanoparticles

Anand, Manish

doi:10.48550/arxiv.2101.03356

Cited by 3 publications

(3 citation statements)

References 42 publications

(53 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dipolar interaction also drastically modifies the magnetic properties in such cases [33][34][35][36][37][38]. For instance, V. Russier studied the magnetic properties, and orientational structure for spherical assembly of MNPs arranged in square and hexagonal lattices at temperature T = 0 K [36].…”

Section: Introductionmentioning

confidence: 99%

Hysteresis in Two Dimensional Arrays of Magnetic Nanoparticles

Anand

2021

Preprint

Self Cite

View full text Add to dashboard Cite

We perform computer simulations to probe the magnetic hysteresis in a two-dimensional (L x ×L y ) assembly of magnetic nanoparticles as a function of dipolar interaction strength h d , temperature T , aspect ratio A r = L y /L x , and the applied alternating magnetic field's direction. In the absence of magnetic interaction (h d ≈ 0) and thermal fluctuations (T = 0 K), the hysteresis follows the Stoner and Wohlfarth model, as expected. For weak dipolar interaction and substantial temperature, the hysteresis has the dominance of superparamagnetic behaviour, irrespective of the applied magnetic field's direction and A r . Interestingly, the hysteresis curve has all the characteristics of antiferromagnetic interaction dominance for A r ≤ 6 and considerable dipolar interaction strength (h d > 0.2), which is independent of applied magnetic direction. When the magnetic field is applied along the system's shorter axis (x-direction), a non-hysteresis straight line is observed with large h d . In the case of the magnetic field applied along the long axis of the sample (y-direction), ferromagnetic interaction dominates the hysteresis for large h d and A r > 6. Irrespective of h d and applied magnetic field's direction, the coercive field µ o H c and remanence M r are minimal for A r ≤ 6 and significant temperature. They are found to increase with h d when A r is enormous.Remarkably, the variation of hysteresis loop area E H as a function of these parameters is the same as that of the coercive field variation. We believe that the concepts presented in this work are relevant in various technological applications such as spintronics and magnetic hyperthermia, in which such self-assembled nanoparticle arrays are ubiquitous.

show abstract

Section: Introductionmentioning

confidence: 99%

Hysteresis in Two Dimensional Arrays of Magnetic Nanoparticles

Anand

2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is not unexpected, recalling the presence of the ubiquitous dipolar interaction [29][30][31]. The latter is long-ranged and anisotropic, which has a diverse effect on the morphologies and magnetic properties of an assembly of MNPs [32][33][34]. Further, the constituting MNPs may form clusters in many different ways.…”

Section: Introductionmentioning

confidence: 99%

Non-Uniform Hysteresis in Small Clusters of Magnetic Nanoparticles

Anand

2021

Preprint

Self Cite

View full text Add to dashboard Cite

Using first-principle calculations and kinetic Monte Carlo simulation, we study the local and averaged hysteresis in tiny clusters of k magnetic nanoparticles (MNPs) or k-mers. We also analyze the variation of local dipolar field acting on the constituent nanoparticles as a function of the external magnetic field. The dipolar interaction is found to promote chain-like arrangement in such a cluster. Irrespective of cluster size, the local hysteresis response depends strongly on the corresponding dipolar field acted on a nanoparticle. In a small k-mer, there is a wide variation in local hysteresis as a function of nanoparticle position. On the other hand, the local hysteresis is more uniform for larger k-mer, except for MNPs at the boundary. In the case of superparamagnetic nanoparticle and weak dipolar interaction, the local hysteresis loop area A i is minimal and depends weakly on the k-mer size. While for ferromagnetic counterpart, A i is considerably large even for weakly interacting MNPs. The value of A i is found to be directly proportional to the dipolar field acting on the nanoparticle. The dipolar interaction and k-mer size also enhances the coercivity and remanence. There is always an increase in A i with clutser size and dipolar interaction strength.Similarly, the averaged hysteresis loop area A also depends strongly on the k-mer size, particle size and dipolar interaction strength. A and A i always increase with k-mer size and dipolar interaction strength. Interestingly, the value of A saturates for k ≥ 20 and considerable dipolar interaction irrespective of particle size. We believe that the present work would help understand the intricate role of dipolar interaction on hysteresis and organizational structure of MNPs and their usage in drug delivery and hyperthermia applications.

show abstract

“…As a consequence, it has a far-reaching effect on various magnetic properties of crucial importance such as modified energy barriers, frustrations of spins, changed magnetic dynamics, unique morphology, etc. [20][21][22][23][24]. For instance, in the case of randomly distributed particles and anisotropy axes, the magnetic properties of the system can have similarities to those of spin glasses [25].…”

Section: Introductionmentioning

confidence: 99%

Tailoring Heat Dissipation in Ordered Arrays of Dipolar Coupled Magnetic Nanoparticles

Anand

2021

Preprint

Self Cite

View full text Add to dashboard Cite

The main aim of the present work is to analyse the effect of dipolar interaction strength λ, particle size D and temperature T on the hysteresis mechanism in ordered arrays of magnetic nanoparticles (MNPs) using computer simulations. The anisotropy axes of the MNPs are assumed to have random orientation to mimic the real system. In the absence of thermal fluctuations and dipolar interaction, the hysteresis follows the Stoner and Wohlfarth model irrespective of D, as expected. The hysteresis loop area is minimal for particle sizes D ≈ 8 − 16 nm at T = 300 K and λ = 0.0, indicating the dominance of superparamagnetic character. Switching magnetic interaction on is able to move the MNPs from superparamagnetic to a ferromagnetic state even at room temperature; therefore, magnetic interaction of enough strength enhances the hysteresis loop area. Interestingly, the hysteresis loop area is significant and is the same as that of Stoner and Wohlfarth particle even T = 300 K and negligible dipolar interaction for ferromagnetic MNPs (D > 16 nm). The coercive field µ o H c and blocking temperature T B also get enhanced with an increase in λ and D. The rigorous analysis of the coercive field µ o H c vs temperature data also reveals significant deviation from T 3/4 dependence of µ o H c because of dipolar interaction.The amount of heat dissipated E H and µ o H c decrease rapidly with T for D ≈ 8 − 16 nm and λ ≤ 0.6. On the other hand, E H and µ o H c depend weakly on T with D > 16 nm, even in the weak dipolar limit. The present work should provide a better understanding of magnetic hyperthermia to researchers working on this subject. For physicists, it would be interesting to test experimentally the results described in this article.

show abstract

Dipolar Interaction and Sample Shape Effects on the Hysteresis Properties of 2d Array of Magnetic Nanoparticles

Cited by 3 publications

References 42 publications

Hysteresis in Two Dimensional Arrays of Magnetic Nanoparticles

Hysteresis in Two Dimensional Arrays of Magnetic Nanoparticles

Non-Uniform Hysteresis in Small Clusters of Magnetic Nanoparticles

Tailoring Heat Dissipation in Ordered Arrays of Dipolar Coupled Magnetic Nanoparticles

Contact Info

Product

Resources

About