Brush Industries Long Life Magnetic Recording Heads DesignGuide 2-2

Traditional solution

Condition of a ceramic coated traditional material magnetic head showing what the industry has considered a solution for the scalloping problem. The stripe width has been decreased from .030/.040 to .008/.016. The reduced distance between the two ceramic areas lessens the amount of scalloping and extends operating life. This solution has some definite disadvantages. The exposed magnetic material on either side of the head gap is only .004 to .008 wide. This is not enough magnetic material to be able to efficiently record or overwrite high coercivity media. This is not a viable solution for high coercivity write heads. In addition this limits head manufacturers to using old technology stamped core laminations versus the modern practice of using photo-etched laminations in a frame.

Supermium® solution

Condition of a ceramic coated Supermium® core magnetic head, showing wear characteristics exhibited throughout the life of the head. The Supermium® core material is almost as hard as the ceramic. Rc 50 for Supermium® and Rc 60 for Ceramic. Scalloping does not become a factor. In addition the hard Supermium® core material retains its original surface finish much longer than the softer traditional core material, significantly extending card or ticket life. When laminated this material has adequate magnetic properties to be used for encoding high coercivity media, currently up to 2750(oersted).

Spacing Loss

Spacing loss reduces the flux contribution from magnetization spaced away from the head surface.

The Complete Handbook of Magnetic Recording 4th Edition By Finn Jorgensen McGraw Hill 1995.