General magnetostatic shape–shape interactions

General magnetostatic shape–shape interaction forces and torques

“…For large separation distances, the interaction energy, force, and torque between two objects of random shape are well approximated by the standard dipolar interaction, replacing the actual magnetic moment distribution in each object by the net overall moment. When objects approach each other more closely, the interactions begin to deviate significantly from the simple dipolar form, and shape effects become important [4].…”

“…The shape amplitude formalism used in this paper has been described at length in a number of previous publications [4,[8][9][10][11] and will not be repeated here. In the next section, we will describe briefly the relations most relevant to the problem of force and torque computations.…”

Magnetization Dynamics in Arrays of Quantum Dots

“…In this scenario, the interactions between pairs of intra-dot domains render quite involved and time-consuming the computational task of solving the LLG equation, requiring highly technical numerical expertise or specialized software to handle the computational complexity. The second approach, called macrospin model [24,26], is appropriate to describe the magnetization time evolution of assemblies of small nanoparticles, such that each dot magnetization can be described by a single magnetic moment within the QD volume. What we mean by small is unfortunately system dependent, but some known data for spherical MQDs can be found in Figure 1 as reference.…”

Coercivity reduction in a two-dimensional array of nano-particles

“…The volume of such nano-particle scales then as πa 2 h. Due to the non-spherical form the present nanoparticle will have non-negligible demagnetizing-field contributions [20,21], the calculations of which might be a non-trivial task in general [22]. The demagnetizing factors can be obtained [23,24] for a general cylinder with an elliptic base [25]. To simplify the calculations, we can use the formula for the demagnetizing factor along the zaxis of an oblate ellipsoid (which has a difference below 5% relative to the exact solution given in Fig.…”