Photopyroelectric calorimetry down to 10 K

Abstract

In photopyroelectric calorimetry thermal conductivity, thermal diffusivity and specific heat are measured simultaneously from the same heating or cooling run. As it provides a good signal-to-noise ratio with small temperature gradients, it is well suited to study the critical behaviour of phase transitions. Up to now, it has been mainly used above 77 K. In this work we implement the cryogenic set-up to work down to 10 K. The troubles introduced by the cryostat vibrations and by the freezing of the coupling grease are analysed. This set-up has been used to characterize the critical parameters of the antiferromagnetic SmMnO3, which agree with the three-dimensional XY universality class.