The Shift of the Spin Flip Temperature of α-Fe₂O₃Fine Particles

Abstract

The particle size dependences of the spin flip transition temperature (Morin temperature) and of the lattice constant of α-Fe 2 O 3 were studied experimentally. With decreasing particle size, it was found that the Morin temperature shifts downwards and crystal lattice expands both in a - and c -axis directions. As the origin of the Morin temperature shift, the change of the dipolar magnetic field due to the lattice dilatation was considered. Experimental values were compared to the theoretical calculation of Artmann and a qualitative agreement was obtained.