APPLIED PHYSICS: Highly Heat-Sensitive

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Science  23 Sep 2005:
Vol. 309, Issue 5743, pp. 1967d
DOI: 10.1126/science.309.5743.1967d

The most severe tests of calorimetry are surface processes, where the small number of reaction, binding, or adsorption events limits the amount of heat available for measurement. Fon et al. have constructed a cryogenic suspended SiN calorimeter that has a heat capacity resolution of 0.5 attojoule per Kelvin, compared with a typical state-of-the-art resolution of 1 femtojoule per Kelvin. The fast response of interdigitated AuGe resistance thermometers allows sampling every few microseconds, so that temperature changes can be followed via the fast relaxation of the calorimeter. The authors measured the enthalpy change associated with adsorbing 0.16 monolayers of 4He on a device area of 1.2 × 10−9 m2. The measured value at 2 K corresponds to a heat capacity of 1.4 kB per helium atom, which agrees well with the measured value for He adsorbed on Grafoil. — PDS

Nano Lett. 10.1021/nl051345o (2005).

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