Abstract
About 150 nm sized marks were recorded and readout was performed using a reflection-mode near-field scanning optical microscope (NSOM) in the 4-layered phase-change optical disk structure. Full-width at half-maximum (FWHM) values of the linewidth of the marks recorded at different writing speeds decreased with increasing writing speed. The thermodynamic stability of the submicron-sized marks and its implications are discussed on basis of the surface energy and its effect on the temperature of phase transformation, including crystallization and melting.