Unique Experimental Setup Developments

Specific Heat of ‘Dust’ – Nanocalorimetry

We recently built a SiN membrane based calorimeter specifically designed for microcrystal thin film work. Both the thermometer and heater are realised by self-calibrating, magnetic field independent coulomb blockade thermometers. The nonmagnetic components enable the calorimeter to be used for both magnetocaloric effect and specific heat measurements with the former only requiring a thermometer.  Addenda heat capacities as low as 10pJ/K at 1K can be realized. The setups enable heat capacity measurements at temperatures down to 50mK and magnetic fields up to 15T up to for single crystals smaller than 100 micrometers.

Ultrasensitive Dilatometry under extreme conditions

We built a new ultrasenstive dilatometer measuring length changesvwith a resolution of <0.5pm/sqrt(Hz) by merging conventional thermodynamic instrument design with piezo driven nnaopositioning technology from scanning probe measurements. Capable of operating from room temperature to within a few tens of mk and in magnetic fields up to 15T we measured the ‘breathing’ of a quantum materials caused by quantum oscillations in the meta magnet Sr3Ru2O7.

Ultrasensitive Magnetometry under extreme conditions

We built a Faraday magnetometer based on SiN membranes measuring the force on a magnetic moment in a gradient field. Based on piezo driven in-situ fine adjustment we can track membrane movements with <0.1pm resolution for measurements enabling resolutions as good or better than state-of-the-art MPMS SQUID magnetometers down to 10-8 emu but here in the mK temperature regime and fields up to 15T.

Paramagnetism of thin films

Magnetism in thin film samples is a key characterisation method in for the study of designer heterostructures of quantummaterials and their behaviour in the few-layer limit. By design thin films have an intrinsically small signal size requiring high precision measurements at the resolution limit of magnetic property measurement systems. In this regime otherwise negligible sample holder inhomogeneities as well as uncontrolled substrate contributions can invalidate the results of standard procedures.We built a new Macor-based sample holder and analysis method for such high precision measurement in which 99% of the substrate contribution are compensated in-situ. The approach successfully corrects for systematic errors in key quantities such as the saturation moment and enables the proper measurement of Curie-Weiss behaviour in thin film samples.