Plate-like ferrite particles with magnetoplumbite structure and magnetic card using the same

Abstract

The present invention relates to plate-like ferrite particles with magnetoplumbite structure having a composition represented by the general formula of AO.multidot.n{(Fe.sub.1-(a+b) Bi.sub.a M.sub.b).sub.2 O.sub.3 } wherein A is Ba, Sr or Ba--Sr; M is Zn--Nb, Zn--Ta or Zn--Sn; n is from 5.5 to 6.1; a is from 0.001 to 0.005; b is from 0.050 to 0.120; and the ratio of b/a is from 20 to 50. The plate-like ferrite particles with magnetoplumbite structure have an appropriate particle size, a low coercive force, a large saturation magnetization, a small switching field distribution (S.F.D.) and an excellent temperature stability, and a magnetic card containing the plate-like ferrite particles with magnetoplumbite structure.

Dependencies are inferred from the claim text.