The oldest known magnetic substance, magnetite (iron(II,III) oxide; Fe3O4), is a ferrimagnet; it was originally classified as a ferromagnet before Néel's discovery of ferrimagnetism and antiferromagnetism in 1948.
Vanim tuntud ferrimagnet on magnetiit (raud(II,III) oksiid; Fe3O4), alguses klassifitseeriti teda kui ferromagnetit, enne Néeli ferrimagnetismi ja antiferromagnetismi avastamist 1948.