Ground state of magnetocrystals

Vandewalle, Nicolas; Wafflard, Adrien

doi:10.1103/physreve.103.032117

Cited by 5 publications

(4 citation statements)

References 26 publications

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“…Open diamond and dot lines meet for 1/m → 0 around u = −2.55 on figure 5(a). This asymptotic value is slightly larger than the cohesive energy for a square lattice [16].…”

Section: Dipole Reorientation In Growing Magnetotubesmentioning

confidence: 77%

“…When creating magnetostructures, one realizes rapidly that the underlying dipole arrangement is as significant as the contact network between particles. This has been explained using equations ( 1) and ( 2) [9][10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…Please note that folding such 2D lattices leads to the formation of magnetotubes as shown in figure 1. A study of 3D magnetocrystals reveals also some unusual physical features: the highest cohesion is obtained for a hybrid structure made for a stack of hexagonal planes while the hexagonal compact (hcp) structure, known as the densest structure, is less cohesive and nearly unstable [16][17][18]. Moreover it has been proved that there exists an infinite number of stables configurations for the orientation of 8 dipoles at the vertices of a cube, similar to Goldstone modes [10,11].…”

Section: Introductionmentioning

confidence: 99%

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Collective dipole reorganization in magnetostructures

2023

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Neodymium spherical magnets are inexpensive objects that demonstrate how dipolar particles self-assemble into various structures ranging from 1D chains to 3D crystals. Assemblies of these magnets are nicknamed magnetostructures and this paper focuses on a variety called magnetotubes, which are some curved square lattices forming cylinders. We experimentally and numerically observe that such magnetotubes can self-buckle, above a critical aspect ratio. In fact, the underlying dipolar ordering of such structures is found to exhibit a collective reorganization, altering the mechanical stability of the entire system. We identify the conditions in which these phenomena occur, and we emphasize that metastable states coexist. This suggests that a wide variety of magnetostructures, including chains and magnetocrystals, may collapse due to the coexistence of multiple ground states and global reorientation of dipoles.

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“…Open diamond and dot lines meet for 1/m → 0 around u = −2.55 on figure 5(a). This asymptotic value is slightly larger than the cohesive energy for a square lattice [16].…”

Section: Dipole Reorientation In Growing Magnetotubesmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Collective dipole reorganization in magnetostructures

2023

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“…The particle-particle interactions are calculated considering that each particle j is a dipole with magnetic moment 𝝁 j = μj , with = | j | , taken to be identical for all particles j. Following [17,18], the dipole-dipole magnetic force on the particle i caused by all the other j particles is given by: where 0 is the vacuum magnetic permeability, ij = i − j represents the vector joining the centers of the particles, r = | | and the unit vector…”

Section: Magnetic Forces: Particle-particle Interactionsmentioning

confidence: 99%

Experimental and numerical investigation of the compression and expansion of a granular bed of repelling magnetic disks

et al. 2022

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We studied experimentally and numerically the compaction and subsequent expansion dynamics of a granular bed composed of cylindrical repelling magnets contained in a two-dimensional cell. The particles are firstly compressed vertically with a piston at a given strain rate until a maximum force is reached. The piston is then removed at the same strain rate while the bed expands due to the magnetic repulsion of the particles. In the experiments, two different initial configurations were generated, a standard and a loose packing bed. The standard packing bed was simulated, and modelling the dry friction between the magnetic particles and the walls of the cell was crucial for the correct description of the compression and expansion dynamics. We found that the force acting on the piston increases continuously and exponentially with the piston stroke during compression, being very sensitive to the initial packing conditions of the bed. In contrast, a history-independent exponential decrease of this force was found during the expansion phase. The hysteresis in the system was quantified in terms of the average displacement of the particles. The continuous compression contrasts with the sudden force drops observed during the compaction of granular materials with direct particle-particle contacts, where stick-slip motion is induced by friction and force chain breakage. Moreover, we found that the short range of magnetic interaction induces density inversion and crystallization of the system. Our results can be useful to develop a new kind of magnetic granular dampers.

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