Phase transitions and undercooling in confined gallium

Phase transitions in submicrometre gallium droplets confined in epoxy resin are revealed by single-energy X-ray absorption spectroscopy using synchrot ron radiation, a technique previously applied in high-temperature studies o f solid and liquid metals. These unconventional measurements are accompanie d by a detailed characterization of samples using scanning electron microsc opy and adiabatic calorimetry measurements. Exceptional undercooling down t o 150 K is confirmed by the present data. Specific heat measurements perfor med during the warming cycles confirmed the presence of three different sol id phases for gallium, namely beta-Ga, gamma-Ga and delta-Ga and the absenc e of the alpha-Ga stable phase at ambient conditions.