Easy axis of magnetization of Fe3C prepared by an electrolytic extraction method

• It is proved that the easy axis of cementite is c-axis of orthorhombic structure.
• The precise magnetic anisotropy energy of cementite has been evaluated.
• The method used in this article can be widely applicable for other materials.

We have determined the easy axis of magnetization of Fe3C (cementite) using a powder specimen prepared by an electrolytic extraction method. The easy axis is determined to be the c-axis (the shortest axis) of the orthorhombic structure with the space group Pnma. The result is different from the one previously reported by neutron diffraction (b-axis). The magnetic energy difference between the easy axis and the average of other two axes is approximately 400 kJ/m3 at 5 K.