Anti-theft sensor marker

Abstract

Abstract An anti-theft sensor marker is disclosed which has good sensitivity characteristics and which does not readily deteriorate due to bending stress. The marker is mainly composed of an alloy ribbon and is employed in an anti-theft system in which the stealing of a commodity previously marked by the marker is determined by detecting a magnetic field of a specific frequency with respect to an incident magnetic field intensity applied to a detection region through the alloy ribbon of the marker when the marker is disposed within the detection region. The alloy ribbon has the constitutional formula ##STR1## wherein, M is at least one member selected from the group consisting of Co and Ni; M' is at least one member selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo; M" is at least one member selected from the group consisting of V, Cr, Mn, Al, platinum metals, Sc, Y, rare-earth metals, Au, Zn, Sn and Re; X is at least one member selected from the group consisting of C, Ge, P, Ga, Sb, In, Be and As; and a, x, y, z, α, β and γ satisfy the relations: 0≦a≦0.3, 0.1≦x≦3, 6≦y≦25, 3≦z≦15, 14≦y+z≦30, 1≦α≦10, 0≦β≦10, 9≦γ≦10, and wherein at least 50% of the structure of the alloy ribbon is composed of fine bccFe solid-solution crystalline grains in which the mean grain diameter, measured as a maximum grain diameter, is not larger than 500 Å.

Inventors

• 👤 Kiyotaka Yamauchi
• 👤 Yoshihito Yoshizawa

Bibliographic Details