I come from a biomedical background which has primarily focused on inductors as an element of a transcranial magnetic stimulator. The way this method works is that a copper coil receives pulses of electric current which generates a changing magnetic field. This changing magnetic field is great for getting past the skull and into the brain, where it generates a reverse-direction electric current, used to treat various diseases and malflictions. We don't call these coils "inductors" nor do we call these neural stimulations "eddy currents". But that's probably what you know them as.
I know that typically, inductors use ferromagnets as a core, because they have a much higher saturation level than other materials, leading to higher inductance. However, I have just read that for magnetic stimulation, it is better to use ferrimagnets because they are non-conductive. The book implies that Eddy currents generated in the core of a conductive ferromagnet would weaken the induced electric current in the brain. Is this really true? This is just just conservation of energy I guess? The book seems to assume that there is a layer of insulation between the copper coil and the conductive ferromagnetic center.
Say you have a copper wire that's immersed in a ferromagnetic material - no insulation between the wire and the material. Does the same result apply? Is it because ferromagnets are insulative relative to copper, meaning they won't pick up much current from the actual pulse, but will only pick up the eddy currents?
Now for my real question. Imagine you had a magical material that was uniformly conductive and uniformly ferrimagnetic. Not a conductive wire in a magnetic substance, but a uniformly conductive and magnetizable material, which I guess was also highly conductive like copper. How would the inductance, or induced current, change here?