Design and properties of a pyroelectric microcalorimeter

A pyroelectric calorimeter consists of a pyroelectric sensor with the sample directly deposited onto one of the electrodes of the sensor. The arrangement is heated by the absorption of intensity modulated radiation at the other electrode of the pyroelectric sensor. In the case of a homogeneously poled pyroelectric sensor, the quotient of the pyroelectric current, gained at modulation frequencies ω below and above ω=2D/d², with D the thermal diffusivity and d the thickness of the pyroelectric sensor material, directly yields the quotient of the heat capacity of the pyroelectric materials and the sample. Experimental results are shown with a 30 μm thick LiTaO₃ crystal and 25 μm and 9 μm thick PVDF (polyvinylidene fluoride) films as calorimeter materials, and with 25 μm thick Ag-foils and a 1.25 μm thick polyglutamate Langmuir-Blodgett film