FM ordering is accompanied by a negative volume strain. With increasing temperature, there is a cation disorder or charge transfer induced LS–HS transition of the Co 3 C ion at the 16d site

The magnetic nature of Co 3 O 4 reveals an incommensurate AFM order below T N [ 15 ], with the exchanges of Co 2 C ions at the 8a site and Co 3 C ions at the 16d site.