Manufacturing of permanent magnet has a configuration like the following figure. A ferromagnetic material is heated up till it reaches its Curie value then exposed to a very strong magnetic field in order to orient the poles of the material in one direction.
The stronger the magnetic field, the good orienting is.
To increase the value of magnetic field increase the number of turns and current
You should know what temperature you should heat the material to, taking in consideration heat transfer and the required time to align all grains.
We can get a DC current from an AC one using a rectifier like diode bridge.