Biased four-point probe resistance.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Electrical Engineering

Background:

• Four-point probe measurements are standard for determining material resistance.
• Temperature fluctuations during measurements can introduce errors in resistance determination.
• Understanding and mitigating measurement biases is crucial for accurate material characterization.

Purpose of the Study:

• To investigate the implications of switching current polarity in four-point probe resistance measurements.
• To analyze the bias induced in temperature-dependent DC resistance due to temperature changes during current reversal.
• To develop an analytical expression for this measurement bias.

Main Methods:

• Theoretical analysis to derive an analytical expression for the bias.
• Experimental validation using a superconducting Niobium (Nb) thin film.
• Systematic variation of cooling rate (dT/dt) and voltage change with temperature (dV/dT).

Main Results:

• A bias in temperature-dependent DC resistance is induced by temperature variations during current polarity switching.
• The bias increases monotonically with the cooling rate (dT/dt) when dV/dT is constant.
• The bias also increases with dV/dT, reaching up to 13% of the room-temperature resistance.

Conclusions:

• Switching current polarity in four-point probe measurements can introduce significant bias in temperature-dependent resistance.
• The magnitude of this bias is dependent on both the cooling rate and the voltage-temperature characteristics of the material.
• Accurate resistance measurements require careful consideration of temperature stability during current polarity reversal, especially for materials like superconducting thin films.