Phase Transitions in Confined Gallium Droplets

Abstract

Phase transitions in submicrometric Ga droplets confined in epoxy resin are studied by combining energy-dispersive x-ray diffraction (EDXRD), x-ray absorption fine structure, and single-energy x-ray absorption. The restricted fluid is undercooled down to 150 K while the melting point is depressed down to 254 K. Melting and freezing are sharp processes occurring with temperature broadening of 1 and 10 K, respectively. EDXRD patterns are consistent with that of $\beta -\mathrm{Ga}$, while the stable phase at ambient conditions $\alpha -\mathrm{Ga}$ is not found to exist. Appearance of $\gamma -\mathrm{Ga}$ and $\delta -\mathrm{Ga}$ solid phases and relevance of present results to recent studies of Ga confined in porous glass are discussed.