Nanomaterials exhibit unique electrical, magnetic and thermal functionalities that are of great interest to engineers. Improved ability to measure miniscule thermal changes in nanomaterials during chemical processes will foster novel device designs.
To measure the very small heat capacities (thermal energies required to change the temperatures) of nanomaterials, improved calorimetry is required.
The EU-funded project 'Atto-calorimetric tools to explore material properties in the nanoscale' (ATTOCALMAT) was initiated to deliver a tool for thermal measurements on small scales. The developed technique, called the microsecond-pulsed steady-state nanocalorimetry method, combines the signal enhancement of fast scanning with advanced signal averaging of steady-state techniques. Ultra-fast heating rates are key to high resolution and signal averaging takes care of measurement anomalies.
Scientists sought to exploit it for the nanochip measurement of heat capacities of single nano-objects with respect to temperature, applied electrical or magnetic fields and time. The latter dependencies are of critical importance to the development of new magnetic storage, spintronics or photonics devices.
ATTOCALMAT developed an experimental measurement setup with newly designed nanocalorimeters and a superconducting coil for generating magnetic fields. The new calorimeters have reduced sensing areas to increase selectivity. The instrumentation is synchronised such that the background pulsed heating is executed while external variables such as magnetic field, gas pressure and temperature are controlled. The setup is an important project contribution to analysis of size effects on heat capacity.
Researchers successfully applied the new experimental setup to the study of the interface reaction between palladium, nickel and silicon to form silicides. Silicides are two-element compounds in which one is silicon. They also conducted simultaneous nanocalorimetric and synchrotron radiation experiments yielding important insight into mechanisms of formation of the silicide phase.
Further optimisation and realisation of the complete pulse-heating, small-area devices will facilitate important new measurements of small-scale heat changes during chemical processes. Such measurements will enable scientists and engineers to produce knowledge-based designs for new devices in fields including magnetic storage, spintronics and photonics.