Experimental methods to obtain remnant moment-thickness product (Mrδ) reduction in the laminated antiferromagnetically coupled (LAC) recording media is described. The results indicate that the reduction in Mrδ (or, indirectly, a reduction in noise) can be obtained by altering the antiferromagnetic coupling constant J, or by the parameters of the underlayer such as anisotropy constant (Ku2), thickness (t2), etc. A method to enhance J by intrinsic means is proposed by which a high exchange field of about 1900 Oe can be obtained. Thermal energy has been found to help in obtaining a Mrδ reduction in LAC media. Substrates with lower surface roughness also enhance the Mrδ reduction.
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