Heating to the curie point would be easier to calculate using E = mcT, but the (T) temperature required to demagnetize is too high, that's why i want to use the method of running an AC current and gradually reducing current to zero. Hammering is another method.
Perhaps if the energy required is...
How would i go about calculating the AC current and overall energy required to demagnetize an Iron plate that has been magnetized by a permanent magnet?