Adsorption transition of a grafted ferromagnetic filament controlled by external magnetic fields

Abstract

Extensive Langevin dynamics simulations are used to characterize the adsorption transition of a flexible magnetic filament grafted onto an attractive planar surface. Our results identify different structural transitions at different ratios of the thermal energy to the surface attraction strength: filament straightening, adsorption, and the magnetic flux closure. The adsorption temperature of a magnetic filament is found to be higher in comparison to an equivalent nonmagnetic chain. The adsorption has been also investigated under the application of a static homogeneous external magnetic field. We found that the strength and the orientation of the field can be used to control the adsorption process, providing a precise switching mechanism. Interestingly, we have observed that the characteristic field strength and tilt angle at the adsorption point are related by a simple power law.

Dynamic response of a ferromagnetic nanofilament under rotating fields: effects of flexibility, thermal fluctuations and hydrodynamics

“…In order to represent the system introduced above, we use a conventional bead-spring modeling approach, 42 whose main characteristics are summarized in the sketch shown in Fig. 1.…”

“…In the latter case, equilibrium properties have been largely addressed for ferromagnetic nanofilaments. [39][40][41][42] However, despite their great potential interest, studies on out of equilibrium properties of such latter systems are still very scarce due to the higher complexity and computing cost involved in its modeling, since long-range hydrodynamic interactions can not be disregarded under such conditions. 43,44 In this work we take a first step to fill such theoretical gap by studying how chain flexibility, background thermal fluctuations and hydrodynamic interactions affect the dynamics of ferromagnetic nanofilaments under an external drive.…”

Dynamic magnetic properties of magnetosomes

“…From a modelling perspective, the structural and static magnetic properties of chains of magnetic nanoparticles have been studied extensively using computer simulations, notably by Kantorovich et al [29][30][31][32][33][34][35][36][37]. In these investigations, not only linear chains of magnetic particles have been considered, but also more exotic architectures such as Y-shaped, X-shaped, and ring SMPs.…”

Elasticity of Semiflexible ZigZag Nanosprings with a Point Magnetic Moment

“…One way to realize this coupling is by embedding magnetizable colloidal particles into an elastic polymeric matrix [ 33 ]. At the single-molecule level, magnetic filaments consisting of magnetic or magnetizable beads linked together by short polymer segments have been studied both theoretically and experimentally [ 34 , 35 , 36 , 37 , 38 , 39 ], and have been used in applications, e.g., in order to construct an artificial flagellum [ 40 ]. In a recent publication, we theoretically analyzed the elastic response of a grafted semiflexible nunchuck (two weakly bending rod-like polymers linked together by a soft hinge) having a magnetic moment at the free end.…”