Thermopower measurement of a thermocouple under magnetic fields.

Thermocouple Measurement

In 1822, Thomas Seebeck, an Estonian physician, accidentally joined semicircular pieces of bismuth and copper (Figure 1) while studying thermal effects on galvanic arrangements. A nearby compass indicated a magnetic disturbance. Seebeck experimented repeatedly with different metal combinations at various temperatures, noting relative magnetic fi eld strengths. Curiously, he did not believe that...

Hot-electron thermocouple and the diffusion thermopower of two-dimensional electrons in GaAs.

A simple hot-electron thermocouple is realized in a two-dimensional electron system (2DES) and used to measure the diffusion thermopower of the 2DES at zero magnetic field. This hot-electron technique, which requires no micron-scale patterning of the 2DES, is much less sensitive than conventional methods to phonon-drag effects. Our thermopower results are in good agreement with the Mott formula...

Transient heat flux measurement using a surface junction thermocouple

A new form of surface junction thermocouple sensor has been developed and tested. The novel feature of the design is the use of a tapered fit between two coaxial thermocouple elements to form a thin, robust junction. The gauge has a response time on the order of 1 ms and is suitable for measuring large transient heat fluxes in hypervelocity wind tunnels. Asymptotic analysis is used to demonstra...

Analysis of a Rigid Ferromagnetic Body under Applied Magnetic Fields

Thermopower of quantum nanowires in a magnetic field.

Thermoelectric properties of nanowires in a magnetic field are studied. Magnetic splitting of thermopower peaks associated with electronic energy levels that are degenerate at zero field, leading to the development of separate thermopower peaks at larger fields, are predicted. A scheme is described for measuring thermopower in a circuit containing a nanowire and leads made from the same materia...