Finding the Curie Temperature for Ferromagnetic Materials

The laboratory exercise described in this paper is based on a well-known qualitative demonstration of Curie temperature.1 A long ferromagnetic wire, in the form of a spiral, is attracted to a strong permanent magnet placed near its midpoint (see Fig. 1). The temperature of the wire is increased by passing a current through it. When the temperature reaches the Curie point, the wire becomes paramagnetic and is no longer strongly attracted to the magnet. We have developed this demonstration into a quantitative experiment by providing an accurate way to determine the temperature at which the ferromagnetic-paramagnetic transition occurs.