Title:
MAGNETOPLUMBITE TYPE FERRITE PARTICLE FOR MAGNETIC CARD
Document Type and Number:
Japanese Patent JP3440741
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain tabular magnetoplumbite type ferrite particles having a proper particle size, a low coercive force, a large saturation magnetization value, small in a coercive force distribution S, F, D, value and improved in temperature stability by forming the tabular magnetoplumbite type ferrite particles having a specific composition.
SOLUTION: The tabular magnetoplumbite type ferrite particles have a composition of the formula: AO.n{(Fe1-(a+b)BiaMb)2O3} [A is Ba, Sr or Ba-Sr; M is Zn-Nb, Zn-Ta or Zn-Sn; (n) is 5.5-6.1; (a) is 0.001-0.005; (b) is 0.050-0.120; (b)/(a) is 20-50], a plate surface diameter of 0.30-1.50μm, a thickness of 0.05-0.60μm, a tabular ratio (plate surface diameter/thickness) of 3-7, a coercive force value of 300-1400Oe, a saturation magnetization value of ≥560emu/g, a coercive force distribution S, F, D, of ≤1.30 and temperature stability of -1.5 to +1.5Oe/°C, preferably -1.2 to +1.2Oe/°C. The coercive force value can efficiently be controlled by adjusting a small amount of M.
Inventors:
Akinori Yamamoto
Kazutoshi Sanada
Yoshihisa Yamamoto
Kazutoshi Sanada
Yoshihisa Yamamoto
Application Number:
JP6744897A
Publication Date:
August 25, 2003
Filing Date:
March 04, 1997
Export Citation:
Assignee:
Toda Kogyo Co., Ltd.
International Classes:
G11B5/706; G11B5/855; H01F1/11; C01G49/00; (IPC1-7): C01G49/00; G11B5/706; H01F1/11
Domestic Patent References:
| JP6231930A | ||||
| JP8115518A |
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