Magneto-plumbite ferrite particles for magnetic card, process for producing the same, and magnetic card using the same

摘要

Magneto-plumbite ferrite particles for magnetic cards, which particles are of formula (I) AO.n{ (Fe1-(a+b)BiaMb)2O3} (I) wherein A is at least one metal selected from Ba, Sr and Ca; M is either Co and Sn or Co, Ti and Sn; n is from 5.5 to 6.1; a is from 0.001 to 0.010; and b is from 0.010 to 0.200; and in which particles the change of coercive force with temperature from -10 to 120 DEG C is from -1.5 to +1.5 Oe/ DEG C.