Experimental Studies for Film Structure of TbCo Magnetooptical Disk

The authors discuss how the interference layer thicknesses affect the figure of merit (R × ¿K) of quadrilayer TbCo magneto-optic disks. Disk samples consisted of an Al reflecting layer, a frist Si3N4 interference layer (O.L.), a TbCo recording layer and a second Si3N4 interference layer (U.L.), all of which were sputtered onto transparent substrate. Varying the U.L. thickness had little effect on the reflectance R or Kerr rotation angle ¿K, but both changed significantly in response to changes in the O.L. thickness. This result could be attributed to phase differences generated within the O.L. layer.