Characterization of amorphous TbFeCo films for magneto-optical media

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Abstract
Sputter-deposited amorphous TbFeCo films can exhibit magneto-optical Kerr rotation and are leading candidates for erasable optical storage media. Thirty-two TbFeCo samples, deposited on quartz substrates in four different sputtering runs, were characterized by RBS, VSM, Kerr loop tracing, and polarization microscope photographs. Both Tb- and Fe-rich samples were deposited, with room-temperature coercivities ranging from 1 kOe to over 6 kOe. Kerr rotations varied from 14 to 32 min of arc (film side) and from 19 to 21 min of arc (substrate side). Domain photographs, using fields just below coercivity to initiate reversal at inherent nucleation sites, show domain shapes that vary from irregular structures with internally striped reversal to rather circular, well-reversed domains. The shape of observed domains and their internal magnetization patterns are related to composition and compared with important magneto-optical properties such as coercive field Hc and Kerr rotation θK. Variability of these properties across different sputtering runs and within the same run are also discussed.