Automated Setup for Van Der Pauw Hall Measurements

An automated setup for measuring electronic transport properties, i.e., the Hall coefficient and resistivity versus temperature, was developed for noninvasive characterization of different types of samples with a square shape. This setup allows characterization of thin-film samples without modifications of their shape or patterning on their surface, thus allowing further tests or practical applications. Measurements are based on the Van der Pauw method and the lock-in amplifier technique, which allow achieving quality measurements in highly noisy environments, as is the case for ceramic materials in variable temperatures. Measurements can be made in the range of temperatures from 7 up to 320 K and dc magnetic fields from 0 to 1 T. A detailed description of the setup and the discussion of the methodology of measurements are presented. This setup presents important advantages in comparison with the black-box system that is found in sophisticated equipment. Its modularity makes it transparent for a user, which is a feature that allows an operator to easily check, replace, adapt, and update parts of the system. The system has been optimized for characterization of superconducting samples. As a test of the system performance, we present measurements on Ag films and superconducting samples showing good-quality data, even for the most overdoped samples, for which we have the smallest Hall voltages.