A FULLY AUTOMATED PRECISE ELECTRICAL-RESISTANCE MEASUREMENT SYSTEM

A fully automated precise electrical resistance measurement system for more than one sample has been constructed. Conventional four-probe me asurements with van der Pauw and Montgomery configurations are possibl e with this system. Resistance measurements in the range of a few mu O mega to a few G Omega are possible for six samples at a time from room temperature down to liquid-helium or liquid-nitrogen temperatures wit h a temperature control accuracy of better than 10 mK. The design feat ures of the system with special reference to the low-noise switching m ethods of currents and voltages are described in detail. Precision of the results thus obtained using this system are highlighted for a few superconducting and semiconducting samples. (C) 1996 American Institut e of Physics.