Magneto-optic Write-Head Characterization Using a Garnet Imaging Film

A magneto-optic transducer comprising of a magnetic garnet film with inplane magnetization and a reflective layer is used to generate an image that reveals information on the write field of perpendicular write heads. By evaluating the local image contrast a measure that correlates with head efficiency and over-write is derived. The contrast distribution provides dimensional information and is sensitive to magnetic defects at the air baring surface and deficiencies of the overall magnetic writer performance. The method is non-destructive and when integrated into an automated test system can be applied on the row-bar, slider or head gimbal assembly level.