Structural Transformations in the Bulk Ga–In Melt: NMR Studies

Recently, interest to the Ga–In binary alloy increased remarkably because of its new applications in biology, medicine, flexible robotics, and wearable electronics. We present detailed studies of the evolution of the ⁷¹ Ga and ¹¹⁵In NMR spectra within the temperature range between the complete melted and complete frozen states of the bulk Ga–In alloy aimed to find evidences for the liquid–liquid transition. The Ga–In alloy composition was close to the eutectic point for α-Ga. While the structural transformations were revealed in the supercooled pure gallium and some gallium alloys under nanoconfinement, they were not found in their bulk counterparts, in spite of being theoretically predicted for pure gallium. Changes in the lineshapes and line splitting were found for both gallium and indium isotopes between 277 and 268 K upon cooling and between 250 and 260 K upon warming. The resonance lines within these temperature ranges were deconvolved into two components. Measurements during additional thermal cycles and the analysis of the Knight shifts and intensities of the components proved the occurrence of the liquid–liquid-phase transitions.