Recording properties of multilayered thin film media

The recording properties of layered film media, including the bit error rate, have been measured for comparison with the results found on single layer film media. This investigation centered on the ability of magnetostatic coupling between layers to affect the magnetic performance in ways other than noise reduction. Multilayered magnetic films were fabricated with interlayer thickness from 25 to 330 Å and with one to six magnetic layers using a CoPtCr alloy on a Cr underlayer. In most tests the single layer media perform better than the multilayer media, but the differences are small and do not appear to influence the error rate significantly. The largest distinguishing feature. is the improvement in the signal-to-noise ratio which comes from two thin layers that are coupled magnetostatically. This leads to an improvement of up to four orders of magnitude in the bit error rate for the bilayer media. Increasing the number of layers gives additional improvement