Specific heat is a powerful probe offering insights into the entropy and excitation spectrum of the studied material. While it is well established, a key challenge remains the measurements of microcrystals or thin films especially in the sub-Kelvin, high magnetic field regime. Here we present a setup combining the high sensitivity of SiNx membrane based calorimetry with the absolute accuracy of Coulomb blockade thermometry to realise a nanocalorimeter for such tasks. The magnetic field independent technique of Coulomb blockade thermometry provides an on-platform thermometer combining a primary thermometry mode for in-situ calibration with a fast secondary mode suitable for specific heat measurements. The setup is validated using measurements of a 20 μg sample of Sr3Ru2O7 achieving a resolution on the order of 0.1 nJ/K at 500 mK and an absolute accuracy limited by the determination of the sample's mass. Measurements of CeRh2As2 further highlight the benefits of measuring microcrystals with such a device.
@article{arxiv.2507.11327,
title = {Coulomb blockade thermometry based nanocalorimetry},
author = {Mari C. Cole and Maximilian T. Pelly and Craig V. Topping and Thomas Reindl and Ulrike Waizmann and Jürgan Weis and Andreas W. Rost},
journal= {arXiv preprint arXiv:2507.11327},
year = {2025}
}