Electrical transport measurements like resistance, Hall effect and current-voltage spectroscopy are probes of electron interactions in solids. Scientists use these tools to detect phase changes such as superconductivity, magnetic ordering, or metal-insulator transitions. Electrical transport can also quantify the concentration and mobility of charge carriers or probe the bandgaps in semiconductors and superconductors.
Heat capacity measurements probe the ability of a sample to absorb heat – it quantifies the material’s specific heat and entropy which are fundamental thermodynamic quantities. Entropic effects in solids that can be probed with heat capacity include the magnetocaloric effect and phase transitions such as metal-insulator, superconductivity, or magnetic ordering. In thermal transport, a temperature gradient is induced in a material to measure its thermal conductivity as well as the thermoelectric effect to determine the Seebeck coefficient. These are important transport quantities for similar reasons as listed for electrical transport, as well as being essential in characterizing materials used in thermoelectric power generation and refrigeration.
Vibrating Sample Magnetometry is a fast and sensitive technique to determine a sample’s magnetic dipole moment. The moment arises from the material’s magnetization density which is a fundamental thermodynamic quantity. This tool can be used to study phenomena such as superconductivity, ferromagnetism, superparamagnetism and magnetic frustration. Torque magnetometry probes the magnetic anisotropy of a small sample and gives a unique insight into the microscopic arrangement of magnetic spins. This technique is widely used in the development of magnetic recording media.