Patent ID: 6864793

Claim:
A magnetic marker comprising a magnetically switchable wire formed of a magnetic material and adapted to undergo a sharp magnetic inversion, or major Barkhausen discontinuity or generation of pulses when an alternating field of an intensity higher than the coercive force thereof is applied thereto, said magnetically switchable wire having a diameter of 70 μm to 110 μm and a length of 40 mm or less and being formed of at least one magnetic material having a dendrite structure and selected from alloys including an alloy consisting mainly of Fe and containing 3 to 5% of Si and 1 to 3% of Ni, an alloy consisting mainly of Fe and containing 3 to 6% of Si and 1 to 4% of Mo, and an alloy consisting mainly of Fe and containing 3 to 5% of Si and 1 to 3% of Co; wherein said magnetically switchable wire has primary arms of dendrite which are oriented at an angle of 10° or less to the axis of said wire.