Its a subtle point but I wanted to point out that all that nonlinearity, yes even in magnets, is due time lag. Apologies for not fleshing out the details but th

Its a subtle point but I wanted to point out that all that nonlinearity, yes even in magnets, is due time lag. Apologies for not fleshing out the details but the “path-dependent internal state” is shorthand for saying that the magnet hasnt really reached thermal equilibrium at any point along the cycle. If you could wait for that to happen there would be no hysteresis. The internal state would then only depend on the temperature (and external fields etc) but not on “the history”. Of course, this kind of consistent physics isnt really relevant for engineering and so people have to add in easier to digest (but ultimately inconsistent and vacuous) ideas like path-dependence.