Fabrication of Simple Apparatus for Resistivity Measurement in High-Temperature Range 300–620 K

A simple and low-cost apparatus has been designed and built to measure the electrical resistivity, (p), of metal and semiconductors in the 300-620-K temperature range. The present design is suitable to do measurement on a rectangular bar sample by using a conventional four-probe dc method. A small heater was made on the sample mounting copper block to achieve the desired temperature. Heat loss from the sample holder was minimized using very low thermal conductive insulator block. This unique design of heater and minimized heat loss from the sample platform provides uniform sample temperature, and also has very good thermal stability during the measurement. The electrical contacts of current leads and potential probes on the sample were made using very thin (42 standard wire gauge) copper wires and high-temperature silver paste. The use of limited components and small heater design makes the present instrument very simple, lightweight, easy to sample mount, small in size, and low cost. To calibrate the instrument, pure nickel sample was used, and two other materials La
_0.7
Sr
_0.3
MnO
₃
(LSMO) and LaCoO
₃
(LCO) were also characterized to demonstrate the characterization capability of this setup. p(T) behavior on these samples was found to be in good agreement with the reported data. The metal-insulator transition for LSMO (T
_MI
= ~358 K) and the insulator-metal transition for LCO (T
_IM
= ~540 K) were clearly observed and these transition temperatures were also consistent with those reported in the literature.