Generalized resonance modes in ferromagnetic spheres

Generalized Resonance Modes in Ferromagnetic Spheres

Abet-In the present work we deal with the resonance modes in small ferromagnetic spheres. The analysis is based on the theory of micromagnetism, proposed by W. F. Brown and an optimization technique. Numerical results are presented for the resonance field, as well as for the resonance modes and the magnetization configuration in the material. The resonance modes described in this work could be ...

Theory of collective spin-wave modes of interacting ferromagnetic spheres

We formulate the theory of the collective spin wave modes of arrays of spherical particles of ferromagnetic material, under the assumption that each sphere in the array is magnetized uniformly. In addition, the intersphere interactions have their origin in the magnetic fields generated by the precessing moments, appropriate to the case where there is no direct physical contact between the spher...

Stray field magnetic resonance tomography using ferromagnetic spheres.

The methodology for obtaining two- and three-dimensional magnetic resonance images by using azimuthally symmetric dipolar magnetic fields from ferromagnetic spheres is described. We utilize the symmetric property of a geometric sphere in the presence of a large externally applied magnetic field to demonstrate that a complete two- or three-dimensional structured rendering of a sample can be obta...

Ferromagnetic resonance

Ferromagnetic Resonance

Ferromagnetism is used to characterize magnetic behavior of a material, such as the strong attraction to a permanent magnet. The origin of this strong magnetism is the presence of a spontaneous magnetization which is produced by a parallel alignment of spins. Instead of a parallel alignment of all the spins, there can be an anti-parallel alignment of unequal spins. This results in a spontaneous...