Development of Ultrafast Scanning Calorimetry by the Liquid Drop Enhanced Cooling Method*

Nitrogen or Helium gas as coolant in the ultrafast scanning calorimetry (UFSC) has the advantage of fast shift between programmed heating and cooling, but less effective for fast cooling when the sample temperature is close to the ambient temperature. Here we introduce the method of liquid drop enhanced cooling method that can break through the bottleneck arising from the ballistic cooling problem. We show here that after controlling the drop size, proper heating loop cuting, avoiding of Leidenfrost effect, the cooling rate reaches up to 10⁵ Kelvin per second, i.e., about 4 orders of magnitude faster than cooling by gas at a 50K difference between the sample and the ambient temperature. This method opens even wider windows for the study of various liquid-solid or solid-liquid transformations.