Numerical Simulation of Mark Formation/Erasure in Phase Change Recording

Design/optimization of the phase change recording media to create proper marks, in size, shape, and quality, needs a robust modeling tool to predict temperature distribution in the constituting layers and model the phase formation during writing/erasure of the information bits. This requires a modeling of the heat transfer (thermal performance) and the crystallization processes. The thermal modeling, which is based on the solution of the heat diffusion equation for finding temperature distribution in the multilayer media, has been done before, using the finite difference techniques. These techniques have limited potentials for modeling real phase change recording media that have a rather more complex geometry. The finite elements method has, on the other hand, the required flexibility for such applications. In this work, we are reporting on development of a numerical simulation tool that uses the finite elements method for heat transfer simulation. ANSYS is used as the source code for the heat transfer simulation, in this application, with the crystallization model then being built into this media. This code has been used to simulate mark formation during writing on grooved plain and planer patterned media. Patterning the phase change material layer looks very promising in controlling the mark size and the mark edge irregularity which lead to timing jitter.