Variable Temperature Seebeck Effect
The Seebeck effect is a phenomenon in which a temperature difference between two dissimilar electrical conductors or semiconductors produces a voltage difference between the two substances.
The voltages produced by Seebeck effect are small, usually only a few microvolts (millionths of a volt) per kelvin of temperature difference at the junction. If the temperature difference is large enough, some Seebeck-effect devices can produce a few millivolts (thousandths of a volt).
Numerous such devices can be connected in series to increase the output voltage or in parallel to increase the maximum deliverable current. Large arrays of Seebeck-effect devices can provide useful, small-scale electrical power if a large temperature difference is maintained across the junctions.
Features and Benefits
In addition to all the advantages inherent in the usage of Joule Thomson Thermal Stages as the source of temperature control in these setups, the MMR Technologies Seebeck Measurement System offers many advantages in scientific applications:
- 50 nVolt resolution in Seebeck Measurements
- Ease of measurement of samples ranging from metals to thin films.
- Highly accurate and highly reproducible results.
- Automatic operation in a single step against an internal reference material.
- Small, compact size.
- Wide range of operation: 70K to 730K
- A wide range of sample types can be measured including single crystals, thin films, wires, etc.
Automation of the thermopower measurements provides the following advantages:
- Continuous computer-controlled tuning of the experimental parameters can produce a temperature gradient with nearly constant
- magnitude and period.
- An order of magnitude increase in the density of collected data is readily achieved
- A consistent data reduction process is used for each set of measurements obtained
Overall, these factors allow the MMR Technologies’ Seebeck Effect Measurement system be incredibly accurate with highly reproducible results.
Temperature dependent thermoelectric power (thermopower) measurements on electrically conductive specimens can provide information about the sign of the majority carrier, the mechanism of charge conduction, and in conjunction with appropriate theoretical models, information on the band structure of the material under investigation. Thermopower measurements are also an effective way of determining the intrinsic properties of samples having an electrical conductivity that is dominated by an extrinsic defect structure. A high sensitivity to structural change makes thermopower measurements an excellent technique for the study of structural phase conditions on the charge transport properties of a given material.
Research into thermoelectric materials is important in the fields of energy conservation and alternative energy sources. Developing better materials is of extreme importance in the industries of:
- Automobiles and Fuel Consumption
- Energy Efficiency
- Alternate Energy Sources
- Thermoelectric refrigeration
- And many other industries and research areas - new ones every year.
These systems share many components with the Hall Effect Measurement systems - and can be sold as stand alone systems or as an upgrade.