Pure iron can have two different crystal structures as its temperature is increased from room temperature to its melting point. At room temperature it is body-centered cubic, between 912 and 1394 C if ...

such as expansion, the production of a crystalline state of the metal ... to be found in all places where structures o. iron are located, the ultimate destruction of such structures is merely ...

In fact, the only thing needed to make them is iron and nitrogen, plus an understanding of crystal structure and some engineering ingenuity. To start things off, what even is a permanent magnet?