Another pede posted a list of compounds that are ferromagnetic. Co and Ni are both on the list and would likely cause a magnet to stick to the skin.
in 2019, MIT did a report on storing medical info below the skin invisible to the eye though vaccines. You guessed it, the research funded by Bill and Melinda Gates foundation. QUANTUM DOTS (microchips?) can be an invisible dye in the vaccine that can only be detected with tech like cell phone apps. The research is a couple years old and discusses using a microneedle patch rather than syringe and needle. 2 years is more than enough time to perfect delivering Quantum Dots Dots in syringe and needle like the Covid vax. So, contrary to Melinda's statement, the technology absolutely exists. https://news.mit.edu/2019/storing-vaccine-history-skin-1218
What are QUANTUM DOTS? Magnetic Quantum Dots are made from Co and Ni. https://pubs.acs.org/doi/10.1021/ja036811v
I'm no scientist and am doing more in depth research but so far it appears to be a reasonable explanation....
Well, although I've worked for years in the engineering and scientific community, I did not know until now that nickel was a ferrous-magnetic element. It never came across my radar, so today I learned something new!
relative permeability: iron 280,000 nickel 600 cobalt 250 air 1
It is understandable that you didn't know. There are some alloys that are better than iron though. I don't know the conditions the numbers above were stated for and because it is so non-linear and dependent on field strength (and other things) that could make a big difference. These all were found in the same table so I assume the same conditions were used. I have been re-reading the motors text from my college years so I had seen this recently.