Magnetic interaction of submicron-sized ferromagnetic rings in one-dimensional array

Abstract

Magnetization characteristics of submicron-sized ferromagnetic rings in a one-dimensional array with various inter-ring distances, l x , were investigated by the magneto-optical Kerr effect and micromagnetic simulation. The onion ͑vortex͒-to-vortex ͑onion͒ transition fields were found to be proportional to 1 / l x n with n = 1.36 ͑0.79͒, instead of being a simple dipole interaction model ͑n =3͒. It was demonstrated that the transition mechanism and the inter-ring dependence are governed by the energy gain originating from the deformation of the local vortex. As a result, exchange energy as well as magnetostatic energy play important roles in the magnetization reversal of ring array.

Spherical magnetic nanoparticles: Magnetic structure and interparticle interaction

“…In this first calculation, we just calculate the components of the energy without minimization; we thus obtain the energy at a fixed value of local magnetic structure in the spheres, disregarding the polarization energy. The result is displayed in figure (8 (1, 2), and moreover the proportionality factor is exactly the result of the dipolar interaction, as deduced from (13). We thus conclude that when the structure inside the spheres is frozen, the resulting interaction energy is indeed given by the dipolar interaction between the vortex cores.…”

“…Then, we have to take into account two contributions. The first one which corresponds to (13), is nothing 1)) where H dip (r 12 )ĥ dip (2, 1) is the dipolar field created at r 1 by particle at r 2 and the second one is twice the polarization energy of each sphere in the field of the second one.…”

“…The magnetic behavior of magnetic nanometric particles either isolated or in nanostructured bulk materials is now quite well undertood both from experiments or numerical calculations [1,3,7] but a precise knowledge of interparticles interactions and of their influence on the macrocopic properties is still needed. Indeed, the interparticle coupling has been investigated in a variety of systems, such as nanograins [8,9,10,11,12] nanorings [13,14,15] or cylindrical nanodots [16,17,18,19] with a predominant attention paid on short range effects, such as exchange coupling, or on the influence of the coupling between single domain particles on the global magnetic properties. Conversely the long ranged interaction still deserves attention especially in cases where the magnetic structure of the isolated particle is complex (vortex [20,21,22,23,24] or onion [25,26] states for examples).…”

Magnetization in uniaxial spherical nanoparticles: Consequence on the interparticle interaction

“…For single domain particles, m i ¼ M s v s where M s is the saturation magnetization of the particles, and the orientationsm i result from the minimum of d 112 given in (5). For particles without magnetocrystalline anisotropy, this gives:m 1 ¼m 2 ¼r 12 and d 112 ¼ À2.…”

Magnetization reversal and dynamics in non-interacting NiFe mesoscopic ring arrays

“…5 The OS to VS transition was found to be highly dependent on the edge to edge distance of the rings. [12][13][14] It was shown that beyond a critical distance the magnetostatic interactions between adjacent elements become insignificant, leading to a radical change in the DW dynamics. In case of NiFe ring arrays, the observed critical distance was >100 nm.…”