Metal oxide magnetic substance and a magnetic film consisting thereof and their uses

A magneto optical recording medium comprising a magnetic film on a substrate and an undercoat film between the substrate and the magnetic film, wherein said undercoat film has an epitaxial effect in the region between the substrate and the magnetic film, and wherein the magnetic film consists essentially of a metal oxide magnetic substance represented by the following general formula:

• MeO.n[Ma.sub.x Mb.sub.y Co.sub.z Fe.sub.2-(x+m/3y+2/3z) O.sub.3 ]
• wherein, Me, Ma, Mb, x, y, z, m and n are each as mentioned below:
• Me:
• at least one divalent metal selected from the group consisting of Ba, Sr and Pb,
• Ma:
• at least one trivalent metal selected from the group consisting of Ga, Al, Cr and Rh,
• Mb:
• at least one divalent to tetravalent metal selected from the group consisting of Zn (divalent);
• Ni, In, Sc, Cr, Sb, Bi, Y and Sm (trivalent), and Mo, Ti, Sn, Ta, V, Mn, Ir, Hf, Pd, Nb, Re, Pt, Os, Zr, Tc, Rh, Ge, Ru, W, Te, Pr and Ce (tetravalent) (wherein, the metal represented by Mb is not the same as that represented by Me or Ma)
• x:
• 0<x.ltoreq.0.5
• y:
• 0<y.ltoreq.0.5
• z:
• 0<z.ltoreq.0.5 (wherein, 0<x+y+z.ltoreq.1)
• m:
• an ionic valency of Mb
• n:
• 5.ltoreq.n.ltoreq.6.