Polymorphic phase transitions are common in crystalline solids. Recent studies suggest that phase transitions may also exist between two liquid forms with different entropy and structure. Such a liquid-liquid transition has been investigated in various substances including water, Al 2 O 3 -Y 2 O 3 and network glass formers. However, the nature of liquid-liquid transition is debated due to experimental difficulties in avoiding crystallization and/or measuring at high temperatures/pressures. Here we report the thermodynamic and structural evidence of a temperature-induced weak first-order liquid-liquid transition in a bulk metallic glassforming system Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 22.5 characterized by non-(or weak) directional bonds. Our experimental results suggest that the local structural changes during the transition induce the drastic viscosity changes without a detectable density anomaly. These changes are correlated with a heat capacity maximum in the liquid. Our findings support the hypothesis that the 'strong' kinetics (low fragility) of a liquid may arise from an underlying lambda transition above its glass transition.

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The structure of sputtered amorphous Ge 2 Sb 2 Te 5 was investigated by high energy X-ray diffraction, neutron diffraction and Ge-, Sb-and Te K-edge EXAFS measurements. The five datasets were modelled simultaneously in the framework of the reverse Monte Carlo simulation technique. It was found that apart from Te-Sb and Te-Ge bonds existing in the crystalline phases Ge-Ge and Sb-Ge bonding is also significant in sputtered amorphous Ge 2 Sb 2 Te 5 . According to our results all components obey the '8-N' rule.