I have an old Time-Life book on chemistry, obviously aimed at laypeople, which was published in 1963, and revised a few years later. In a picture spread about the behavior of liquified gases, there was a bit about how you could dunk just about any metal into liquid helium, and it would become an incredibly strong magnet. Similarly, if you cooled circuits to cryogenic temperatures, the conducting metal would lose all resistance to electricity. So they would be ideal for computers, and as a demonstration of this cutting edge technology, there was a photo of a “cryogenic memory plane”, which was “not much bigger than the straight pins alongside it”, that could hold…wait for it…240 bits of memory.
But as I read it, I always wondered if the cost of keeping the helium liquified cancels out any benefit to the magnet or the circuit, and the book said nothing about that. Nor have I seen the concept discussed anywhere else, or since. So, whatever became of this area of research?