Is there any material that will absorb very low frequency radio light? I know that stealth aircraft use radar absorbant materials in their design that absorb radio light best at certain frequencies, but I cannot find any information on materials that are explicitly stated to absorb very low frequency radio light.
I am not looking for any aspect of geometry such as faraday cages - only materials.
a chunk of material will absorb electromagnetic radiation if 1) its characteristic impedance is close to that of a vacuum (to minimize reflections) and 2) if its impedance contains the right amount of ohmic resistance, so as to dissipate the radiation into heat and not re-radiate it.
that said, to interact significantly with EM radiation of any wavelength requires (ideally) that the size of the interacting object be a significant fraction of the wavelength of that radiation. This means that to absorb centimeter-range radar requires something like a centimeter of thickness to the absorbing layer.
Different rules apply if you are interested in just reflecting away the incident EM waves. In this case, a faraday cage will work.
