In situ high-temperature nuclear magnetic resonance characterization of structural evolution in pure gallium melt

The structure of liquid gallium (Ga) is a long-standing issue in the studies of metallic liquids. In this paper we investigate pure Ga melt in the temperature range of 307-1356 K by high-temperature ⁶⁹Ga and ⁷¹Ga NMR. A structural crossover at around 1000 K is revealed through the analyses of NMR observables including the Knight shift and the spin-lattice relaxation time, which may result from the temperature-induced structural evolution of the covalently bonded clusters in pure Ga melt. However, structure and diffusivity anomalies around 450 and 730 K at ambient pressure, which may be induced by the liquid-liquid critical point, are not observed.