Button, Microwave ferrites and ferromagnetics, McGraw-Hill, NY (1962).
Most of the intrinsic resonant behavior in the microwave through millimeter frequency bands are due to cooperative ferromagnetic and ferrite spin-related resonances, antiferromagnetic resonances, microwave atomic transitions, plasmons and plasmon-like resonances, and polaritons at metal-dielectric interfaces.
In magnetic materials, ferromagnetic spin resonances occur in the megahertz to gigahertz to yielding MMW bands.
The intrinsic resonances that do occur are primarily antiferromagnetic, ferromagnetic, water vapor and oxygen absorption bands, surface wave and plasma resonances, and atomic transitions.
Kittel, On the theory of ferromagnetic absorption, Phys.
Bloembergen, On the ferromagnetic resonance in nickel and Supermalloy, Phys.
The foams can be formed from shape memory alloys, shape memory polymers, piezoelectric bimorphs, conductive polymers, ionic polymer gels, ferromagnetic
shape memory alloys, ionic polymer metal composites, ferromagnetics
, hard piezos, liquid crystal elastomers, or annealed polyacrylonitrile fibers.
The domain structure of thick ferromagnetics forms as a result of the minimisation of the interaction energy, the energy of crystallographic anisotropy, magnetostatic and magnetostriction energies.
To solve the problem, the investigators use ferromagnetic materials--iron, nickel, cobalt and their alloys, powders of manganese, silver and aluminium, rare-earth metals (REM) and alloys of these metals.
Magnetically soft and magnetically hard ferromagnetic materials are available.
If the diameter of the particles of the ferromagnetic D is the reduced, the magnetostatic energy, proportional to D3, decreases at a higher rate than the energy of the boundaries between the domains, proportional to D2.
Although the ferromagnetic particles have the multi-domain structure, their interaction with the external magnetic field is reduced mostly to the displacement of the boundaries between the domains.