Evolution of crystalline fraction with time at the location for different initial peak temperatures . Also shown is the normalized peak temperature at the same location and its linear approximation.
Assumed spatial distribution of final crystalline mark after phase change is complete. For the material parameters listed in Table I, theory showed and for an initial temperature pulse width .
Variation in crystalline mark width and tail length with activation energy. Also shown on the upper axis is the calculated corresponding peak temperature. The thermal parameters listed in Table I were used in the calculations. This plot favors small activation energies (and hence reduced peak temperatures) to minimize the width and tail length of the recorded mark.
Plot showing the dependence of final crystalline mark width and tail length on the thermal diffusivity of the medium. Also shown is the corresponding peak temperature for a fixed value of the activation energy .
Evolution of crystalline fraction with time at the location for different initial peak temperatures with and without the effects of latent heat of crystallization. Also shown is the normalized peak temperatures at the same location and calculated for . The latent heat reduces the cooling rate in the medium, thus increasing the volume fraction of crystalline material with modest reductions in peak temperature requirements.
List of thermal, kinetic, and structural parameters for available from literature for the amorphous phase. is the density of the material, and are the melting and crystallization temperatures, respectively, and are the specific heat and thermal conductivity, respectively, is the specific latent heat of crystallization, and is the thermal diffusivity. is the activation energy for crystallization and is the frequency term.
List of phase-change materials used in data storage, their activation energies , and their melting temperatures from literature. Their peak temperatures were calculated according to Eqs. (17) and (20) and the thermal parameters in Table I to achieve a final fraction of crystalline material of 0.9.
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