Automatic thermal conductivity measurements with 3-omega technique.

This article describes an improvement of the 3-omega thermal conductivity measurement system facilitating automatic mode measurement. The use of the electrical circuit with negative feedback to compensate the first harmonic in the voltage signal on the heater-thermometer eliminates manual resistance tuning. To test the procedure, measurements of the thermal conductivity of single crystal sapphire Al2O3 were made. The experimental thermal conductivity value is in a good agreement with the reference data.