A MAGNETIC MARKER

摘要

A small-sized magnetic marker is provided which can be used with good sensitivity in both a so-called large Barkhausen type system and a so-called high permeability type system. The magnetic marker includes a soft magnetic material with its length not longer than 70 mm. When an external alternating field having magnetic field strength of not higher than 0.2 Oe is applied, the soft magnetic material generates abrupt magnetization reversal with a magnetic flux change of not less than 8.0 x 10<-9> Wb. It is preferable that a fluctuation in the magnetic field strength, where soft magnetic material generates the abrupt magnetization reversal, is not higher than 0.1 Oe. <IMAGE>