Microscale Motion Control through Ferromagnetic Films

Benassi, Andrea; Schwenk, Johannes; Marioni, Miguel A.; Hug, Hans J.; Passerone, Daniele

doi:10.1002/admi.201400023

Cited by 5 publications

(14 citation statements)

References 26 publications

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“…Section III elaborates on the technical details of the movement and eddy current implementations. In Section IV, we test our implementation with example simulations, comparing the obtained results to those of previous works on magnetic friction [9] and eddy currents [16,17]. Finally, in Section V we summarize the main points of the article and conclude with thoughts on possible future work.…”

Section: Introductionmentioning

confidence: 94%

“…The films were initialized to a stripe pattern similar to Ref. [9], with approximately 80 nm wide stripes and let relax (Resulting in a system similar to what was shown in Fig. 1), after which the upper film was driven in the +x-direction by a spring moving at a constant velocity v d = 2 m/s for 300 ns.…”

Section: B Magnetic Frictionmentioning

confidence: 99%

“…To see whether the film distance would affect the friction behavior in our tests as it did in Ref. [9], we ran simulations for various film distances, ranging from 20 nm to 80 nm. We started the simulation with the spring already ahead of the slider by 80 nm so that the beginning part of the simulation, where the spring slowly elongates increasing the force, is shorter.…”

Section: B Magnetic Frictionmentioning

confidence: 99%

“…An area currently lacking in micromagnetics is the capability of simulating mechanical motion of magnets and the interplay of motion and the domain dynamics of magnets moving relative to each other. The relative motion of small-scale magnets is relevant in studying phenomena such as magnetic friction [7][8][9][10][11], and for applications such as magnetic force microscopy [12], and micro-and nanomanipulation [13,14]. Despite the scientific interest in these areas, simulation frameworks capable of general micromagnetic simulations coupled with the motion dynamics of the magnets, to the authors' knowledge, do not exist.…”

Section: Introductionmentioning

confidence: 99%

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Moving magnets in a micromagnetic finite-difference framework

Rissanen

Laurson

2018

Phys. Rev. E

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We present a method and an implementation for smooth linear motion in a finite-difference-based micromagnetic simulation code, to be used in simulating magnetic friction and other phenomena involving moving microscale magnets. Our aim is to accurately simulate the magnetization dynamics and relative motion of magnets while retaining high computational speed. To this end, we combine techniques for fast scalar potential calculation and cubic b-spline interpolation, parallelizing them on a graphics processing unit (GPU). The implementation also includes the possibility of explicitly simulating eddy currents in the case of conducting magnets. We test our implementation by providing numerical examples of stick-slip motion of thin films pulled by a spring and the effect of eddy currents on the switching time of magnetic nanocubes.

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Section: Introductionmentioning

confidence: 94%

Section: B Magnetic Frictionmentioning

confidence: 99%

Section: B Magnetic Frictionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Moving magnets in a micromagnetic finite-difference framework

Rissanen

Laurson

2018

Phys. Rev. E

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“…The application of external fields (electric, magnetic, etc.) to the sliding contact was also exploited to tune effectively the frictional response in different kind of tribological systems [5][6][7][8] . Another, subtler route worth exploring is the possible change of adhesion and friction experienced by a nanoslider when a collective property of the substrate, for example some pre-existing ordering is altered under the action of an external field, or of temperature.…”

mentioning

confidence: 99%

Does rotational melting make molecular crystal surfaces more slippery?

et al. 2014

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The surface of a crystal made of roughly spherical molecules exposes, above its bulk rotational phase transition at T= T r , a carpet of freely rotating molecules, possibly functioning as "nanobearings" in sliding friction. We explored by extensive molecular dynamics simulations the frictional and adhesion changes experienced by a sliding C 60 flake on the surface of the prototype system C 60 fullerite. At fixed flake orientation both quantities exhibit only a modest frictional drop of order 20% across the transition. However, adhesion and friction drop by a factor of ∼ 2 as the flake breaks its perfect angular alignment with the C 60 surface lattice suggesting an entropy-driven aligned-misaligned switch during pull-off at T r . The results can be of relevance for sliding Kr islands, where very little frictional differences were observed at T r , but also to the sliding of C 60 -coated tip, where a remarkable factor ∼ 2 drop has been reported.Exploring novel routes to achieve friction control by external physical means is a fundamental goal currently pursued 1 in nanoscience and nanotechnology. The traditional lubrication control of frictional forces in macroscopic mechanical contacts is impractical at the nanoscale, where contacting surfaces are likelier to succumb to capillary forces. Novel methods for control and manipulation of friction in nano and intermediate mesoscale systems are thus constantly being explored. As an example, mechanically induced oscillations were recently shown to reduce friction and wear, an effect that has been experimentally demonstrated 2,3 . Mismatch of relative commensurability of mutually sliding lattices may prevent interlocking and stick-slip motion of the interface atoms, with a consequent friction drop (superlubricity) 4 . The application of external fields (electric, magnetic, etc.) to the sliding contact was also exploited to tune effectively the frictional response in different kind of tribological systems 5-8 . Another, subtler route worth exploring is the possible change of adhesion and friction experienced by a nanoslider when a collective property of the substrate, for example some pre-existing ordering is altered under the action of an external field, or of temperature. In a given state of the substrate, its order parameter magnitude, polarization, critical fluctuations, etc., determines in a unique manner the friction, affecting both the efficiency of * andrea. the slider-substrate mechanical coupling, and the rate of generation and transport of the frictional Joule heat away from the sliding contact. A toy-model study 9 showed that the variation of stick-slip friction, caused by a structural order parameter switching between order and disorder, can indeed be large and observable. Hard to predict on general terms, the frictional variation occurring in a real case will depend on the system, the mechanism, the material. In this work we study the friction experienced by a nanosized island or tip-attached flake sliding over the surface of a molecular crystal made up o...

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Metallic Ferromagnet of La_0.5Sr_0.5MnO₃ with Negative Permittivity and Permeability

Yan

Shen

Yin

et al. 2021

Adv Elect Materials

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geometrical arrangement and the dimensions of unit cells should be made considerably smaller than the characteristics of incident waves. [14][15][16][17][18] For instance, the dimensions of the microwave metamaterials need to be in the millimeter scale. As for infrared or visible metamaterials, only metallic nanostructures, particularly noble metals such as gold and silver with lower ohmic loss can sustain the optical waves. [19,20] To break the size scale and arrangement limits in the periodical-structured material design, random-structured metamaterials with inherent negative ε and/or μ are being sought. [21,22] So far, few theoretical and experimental works have focused on intrinsic single or double negative composites, including metal/ceramic composites and metal/polymer composites. [23][24][25][26][27][28][29][30][31][32][33] These composites are prepared by diluting the ferromagnetic metal or alloy fillers into insulating ceramics or polymers. The behavior of such composites heavily depends on the filler properties.Besides, numerous theoretical, computational, and experimental studies supported in exploring the metal-based composites and the single-phased (homogeneous) metamaterials with intrinsic double negative parameters. The target materials are focused on magnetic semiconducting CdCr 2 Se 4 , In 2−x Cr x O 3 , and La 2/3 Ca 1/3 MnO 3 , motivated by the coupling resonance mechanism between plasma and ferromagnetic resonances. [34][35][36] Veselago. predicted the behavior of metamaterial obtained from the magnetic semiconductor CdCr 2 Se 4 , but could not succeed because of considerable technological challenges in material synthesis. [34] Kussow and Akyurtlu theoretically predicted that, in polycrystalline form, the homogeneous magnetic semiconductor In 2−x Cr x O 3 should exhibit a negative refractive index at ≈10.48 THz. [35] For epitaxial La 2/3 Ca 1/3 MnO 3 film grown on MgO substrate, the negative magnetic μ has been estimated from transmittance data by assuming μ = 1 in the geometry h//μ 0 H. However, the reduction of the anisotropy for different incident angles remains the most difficult. [36] It can thus be concluded that homogeneous or single-phase metamaterials have not yet been realized experimentally.Metallic ferromagnet is believed to be a good candidate for single-phase metamaterials with simultaneous negative ε and μ. Perovskite manganite of La 1−x Sr x MnO 3 (0.2 ≤ x ≤0.5) is a metallic ferromagnet due to the Double-Exchange (DE)Since the electromagnetic metamaterials are artificial materials with subwavelength-scale periodic architectures, they can manipulate electromagnetic waves by exhibiting unusual properties of characteristic negative permittivity ε and permeability μ. However, their fabrication toward reducing the anisotropy for the realization of practical metamaterials is still a challenge. A homogeneous La 0.5 Sr 0.5 MnO 3 with negative properties synthesized by a facile method consisting of the sol-gel method and pressure-less sintering is proposed in this paper. By appropriate...

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Microscale Motion Control through Ferromagnetic Films

Cited by 5 publications

References 26 publications

Moving magnets in a micromagnetic finite-difference framework

Moving magnets in a micromagnetic finite-difference framework

Does rotational melting make molecular crystal surfaces more slippery?

Metallic Ferromagnet of La_0.5Sr_0.5MnO₃ with Negative Permittivity and Permeability

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Microscale Motion Control through Ferromagnetic Films

Cited by 5 publications

References 26 publications

Moving magnets in a micromagnetic finite-difference framework

Moving magnets in a micromagnetic finite-difference framework

Does rotational melting make molecular crystal surfaces more slippery?

Metallic Ferromagnet of La0.5Sr0.5MnO3 with Negative Permittivity and Permeability

Contact Info

Product

Resources

About

Metallic Ferromagnet of La_0.5Sr_0.5MnO₃ with Negative Permittivity and Permeability