In high carrier density correlated electron systems, quantum oscillations are usually detected as tiny oscillations of the magnetization of a sample that appear below 1K. This requires extremely precise and low noise measurement techniques. We have developed two high-sensitivity techniques in our group: an ac suspectibility technique working down to 40 mK, and a magnetometer based on piezoresistive cantilevers for submilimeter-sized samples using a SQUID as a low temperature amplifier, which we were able to run in fields up to 15T. [more]

We use focused ion beam (FIB) microscopy and cleanroom techniques in order to tailor samples of investigated materials on a micron scale for high-precision measurements of charge transport properties. This approach allows greatly enhancing signal-to-noise ratio by optimising the aspect ratio of samples, enables accurately probing resistivity along specific crystallographic directions, and generally facilitates studies of novel compounds, which can only be synthesised as sub-millimetre-sized crystallites. [more]

In the recent years, we have repaired the millikelvin thermal conductivity setup of the MPI-CPfS. It will be used to study unconventional superconductivity, unconventional metals and spin excitations in magnetic insulators. [more]

Conduction of heat in a material via heat currents is a phenomenon analogous to charge transport via electrical currents. Thermoelectric phenomena arise from the entanglement of thermal and electrical transport processes due to (1) heat transport by charge carriers and (2) scattering processes between charge carriers and other heat-carrying quasiparticles, e.g. phonons. By studying the thermal conductivity κ, the thermopower S and the Nernst coefficient N at low temperatures and magnetic fields, we gain valuable information on charge and heat carriers and low energy excitations. [more]