Van der Pauw measurements are suitable whenever you need to characterise a highly conducting material with a four point method and the sample is readily available as a thin slab.

For more information see ProboStat manual section 8.2.5.

These articles refer to ProboStat or other NORECS products, filtered with keywords: 'Van der Pauw, vdp'  

ID=462

Amorphous-cathode-route towards low temperature SOFC

Authors	Andrea Cavallaro, Stevin S. Pramana, Enrique Ruiz-Trejo, Peter C. Sherrell, Ecaterina Ware, John A. Kilner and Stephen J. Skinner
Source	Volume: 2, Pages: 862-875 Time of Publication: 2018
Abstract	Lowering the operating temperature of solid oxide fuel cell (SOFC) devices is one of the major challenges limiting the industrial breakthrough of this technology. In this study we explore a novel approach to electrode preparation employing amorphous cathode materials. La0.8Sr0.2CoO3−δ dense films have been deposited at different temperatures using pulsed laser deposition on silicon substrates. Depending on the deposition temperature, textured polycrystalline or amorphous films have been obtained. Isotope exchange depth profiling experiments reveal that the oxygen diffusion coefficient of the amorphous film increased more than four times with respect to the crystalline materials and was accompanied by an increase of the surface exchange coefficient. No differences in the surface chemical composition between amorphous and crystalline samples were observed. Remarkably, even if the electronic conductivities measured by the Van Der Pauw method indicate that the conductivity of the amorphous material was reduced, the overall catalytic properties of the cathode itself were not affected. This finding suggests that the rate limiting step is the oxygen mobility and that the local electronic conductivity in the amorphous cathode surface is enough to preserve its catalytic properties. Different cathode materials have also been tested to prove the more general applicability of the amorphous-cathode route.
Remark	DOI: 10.1039/C7SE00606C Link

ID=285

Versatile apparatus for thermoelectric characterization of oxides at high temperatures

Authors	Matthias Schrade, Harald Fjeld, Truls Norby and Terje G. Finstad
Source	Review of Scientific Instruments Volume: 85, Pages: 103906 Time of Publication: 2014
Abstract	An apparatus for measuring the Seebeck coefficient and electrical conductivity is presented and characterized. The device can be used in a wide temperature range from room temperature to 1050 °C and in all common atmospheres, including oxidizing, reducing, humid, and inert. The apparatus is suitable for samples with different geometries (disk-, bar-shaped), allowing a complete thermoelectric characterization (including thermal conductivity) on a single sample. The Seebeck coefficient α can be measured in both sample directions (in-plane and cross-plane) simultaneously. Electrical conductivity is measured via the van der Pauw method. Perovskite-type CaMnO3 and the misfit cobalt oxide (Ca2CoO3) q (CoO2) are studied to demonstrate the temperature range and to investigate the variation of the electrical properties as a function of the measurement atmosphere.
Remark	http://dx.doi.org/10.1063/1.4897489 Link