The role of demagnetization factor in determining the ‘true’ value of the Curie temperature

The Curie temperature, TC, is the temperature above which a material loses its long-range ferromagnetic order. Considering the equation of state of a ferromagnet in the mean-field approximation it has been shown theoretically that the value of the demagnetization factor N has a significant influence on the perceived location of TC on the temperature scale. A series of precise measurements of magnetization using two differently shaped single crystals of high-purity gadolinium was carried out to prove this result experimentally and develop a procedure leading to the ‘true’ value of TC.

► Theoretically showed that observed Curie temperature (TC) is sample shape dependent. ► Measured magnetization of two differently shaped high-purity single crystals of gadolinium. ► Experimentally proved that the shape of the sample influences the perceived location of TC.