Patent ID: 7138070

Claim:
A ribbon-shaped magnetic material which is manufactured by colliding a molten alloy to a circumferential surface of a cooling roll so as to cool and then solidify it, the ribbon-shaped magnetic material having an alloy composition represented by the formula of R x (Fe 1−y Co y ) 100−x−y−z B z (where R is at least one rare-earth element, x is 10–15 at %, y is 0–0.30 and z is 4–10 at %), wherein the circumferential surface of the cooling roll has dimple correcting means for dividing dimples to be produced on a roll contact surface of the ribbon-shaped magnetic material which is in contact with the circumferential surface of the cooling roll, the dimple correcting means comprising a plurality of grooves or ridges formed in the circumferential surface of the cooling roll in which the average pitch of the grooves or ridges is in the range of 7.5 to 40.0 μm, and the average height of the ridges or the average depth of the grooves is in the range of 0.5 to 20 μm; the roll contact surface of the ribbon-shaped magnetic material is formed with ridges or grooves which correspond to the grooves or ridges of the dimple correcting means and which are formed by transfer of the ridges or grooves of the circumferential surface of the cooling roll to the roll contact surface of the ribbon-shaped magnetic material; and the dimples produced on the roll contact surface of the ribbon-shaped magnetic material upon solidification thereof include dimples each having an area equal to or greater than 2000 μm 2 , a ratio of the area of the roll contact surface occupied by the thus produced dimples with respect to the total area of the roll contact surface of the ribbon-shaped magnetic material being equal to or less than 10% due to the ridges or grooves formed by the transfer.