Abstract
We discuss the effect of exchange coupling on written bit stability in perpendicular media in terms of resistance to thermal fluctuations. The optimum value of exchange coupling appears to coincide with a medium in which overall interactions, as measured by the δM curve, are close to zero. We calculate the upper limit of the areal density that can be supported by our typical medium and find values of between 80 and 400 Gb/in2, depending on the bit aspect ratio.
