Equilibrium values and dynamics of the net magnetic moment of a system of magnetic dipoles

International Journal of Nonlinear Sciences and Numerical Simulation

2015

The systems of three and four spherical bodies with the dipole magnetic moment have been investigated using a numerical analysis. It was shown that in the initial state with the zero total magnetic moment under the influence of the alternating magnetic field, various regimes of the induced magnetic moment including quasistatic states are established. Revealed are the significant differences between these regimes related to different systems. The magnitude and direction of the magnetic moment of the system, as well the states of dynamic bistability, have been investigated. The possibilities of the induced magnetic moment control due to the changes in amplitude or frequency of the alternating field have been considered.

“…Research funding: This work was sponsored by Ministry of education and science of Russian Federation (N 3.175.2014K -of July 18,2014) …”

Section: Discussionmentioning

confidence: 99%

Section: Initial Equations and Relationsmentioning

confidence: 99%

Dynamically Induced Magnetic Moment of a Magnetic Dipole System

International Journal of Nonlinear Sciences and Numerical Simulation

2015

“…The bodies with dipole moments are considered to be homogeneous and spherical [7]. The dynamic equa tions for the system of dipoles have the following form [8][9][10]: (1) where and are the dipole moment and the angular velocity of the ith dipole ( is the angle of rotation of the ith dipole about the axis j = x, y, z of the Cartesian system of coordinates); J i is the moment of inertia; and α i is the dissipation parameter. In the absence of an external field, the field that is created at…”

Section: Initial Equationsmentioning

confidence: 99%

Orientational transitions in four-row magnetic-dipole lattices

Phys. Metals Metallogr.

2014

Square lattices with four rows of dipoles have been considered. It has been shown that, if there are several stable equilibrium configurations, an external field excites transitions that change the direction of the dipole moments of one of the lattice rows. Orientational transitions in the structure that consists of intersect ing perpendicular lattices have been studied. It has been found that the front of the orientational transition that results in a configuration with rows having alternating directions passes through the region of the inter section of the lattices into the other part of the lattice. The front of the other orientational transitions stops in the region of the intersection. The effect of an external field on certain dipoles located in the region of the intersection makes it possible to control the movement of the orientational transition front; i.e., the front can be forced to pass through the region of the intersection in the initial direction; its direction can be changed, the configuration of the orientational transition can be changed or the front can be stopped in the region of the intersection.

“…Each nanoparticle can rotate about the center of masses. The dynamic equations for this system of magnetic dipoles can be represented as follows [9][10][11]: (1) where and are the dipole magnetic moment and the angular velocity of the ith dipole (ϕ ij is the angle of rotation of the dipole about the axis ), is the moment of inertia, and is the dissipation parameter. The effective field produced at the site of the location of the ith dipole by the other dipoles and by an external magnetic field h is deter mined as follows:…”

Section: Introductionmentioning

confidence: 99%

Equilibrium states of planar arrays of magnetic dipoles with allowance for exchange interaction

Phys. Metals Metallogr.

Семенцов

2015

Equilibrium states of planar square arrays of magnetic dipoles have been studied. It has been shown that, in the presence of exchange interaction, the main equilibrium states are configurations with the orientation of dipoles along the diagonal of the system, along its side, and vortex configurations with different location of the center of the vortex and different magnitudes of the magnetic moment of the system. Condi tions for transitions between equilibrium configurations caused by the planar field that acts on the entire array and by the local normal field acting on part of dipoles entering into the system have been considered. The possibility of transitions between the configurations has been shown and the changes in the total magnetic moment due to the action of the field on separate dipoles of the system has been discussed.