Design and properties of a microcalorimeter

A pyroelectric microcalorimeter is introduced for the measurement of the specific heat of films. It 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. For a homogeneously poled pyroelectric sensor, the quotient for the pyroelectric current, obtained at modulation frequencies omega below and above omega =2D/d ², 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 material and the sample. Experimental results show that with the pyroelectric microcalorimeter it is possible to measure the specific heat of film samples with a thickness in the submicron range and with a sample mass of several micrograms.<>