| abstract |
A magnetic tape having formed on its backcoating layer 5 a recess 10 of prescribed shape capable of yielding an optical contrast to provide optical information with which servo tracking of data tracks on the magnetic layer is effected, the recess having a depth of 0.05 to 1 μm and a width of 0.25 to 30 μm, and the backcoating layer 5 having an arithmetic mean roughness Ra of 4 to 20 nm. |