TY - JOUR
T1 - Electronic transport properties of speer carbon resistor - Experimental results and semi-empirical fits
AU - Rosenbaum, Rachel
AU - Jones, G. E.
AU - Murphy, T.
N1 - Funding Information:
We acknowledge Dr. Bruce Brandt and all the referees for their very constructive suggestions and comments. We are obliged to Drs. Scott Hannahs and Eric Palm for professional and technical assistance at the NHMFL. We thank Mrs. Rachel Rosenbaum for editing assistance. A part of this work was performed at the NHMFL, which is supported by the NSF Cooperative Agreement No. DMR 9527035 and by the State of Florida.
PY - 2005/5
Y1 - 2005/5
N2 - Speer carbon composition resistors, in particular the 470 Ω and 220 Ω 1/2 W grade 1002 resistors, have been used as secondary thermometers at temperatures below 4 K for many years. Their zero field resistances have been measured between 300 K and 4 K using a "dip" probe. Above 10 K, the resistance behavior can be explained using a simple temperature power law, R(T) ≈ R0/T 0.16. The resistance measurements have been extended to 0.02 K using dilution refrigerators. Between 4 K and 0.3 K, the resistances exhibited activated laws having hopping exponents y ≈ 0.5. Below 0.3 K, the 470 Ω resistors exhibit a crossover to a weaker activated law. Crossover resistance expressions suggest that the resistances follow a Mott variable-range hopping (VRH) law below 0.05 K. The low temperature magnetoresistance (MR) data showed changes of less than ±12 % of the zero field resistance values in fields up to 10 T. Fits using the wave function shrinkage and the forward interference models gave only fair agreement with the MR data.
AB - Speer carbon composition resistors, in particular the 470 Ω and 220 Ω 1/2 W grade 1002 resistors, have been used as secondary thermometers at temperatures below 4 K for many years. Their zero field resistances have been measured between 300 K and 4 K using a "dip" probe. Above 10 K, the resistance behavior can be explained using a simple temperature power law, R(T) ≈ R0/T 0.16. The resistance measurements have been extended to 0.02 K using dilution refrigerators. Between 4 K and 0.3 K, the resistances exhibited activated laws having hopping exponents y ≈ 0.5. Below 0.3 K, the 470 Ω resistors exhibit a crossover to a weaker activated law. Crossover resistance expressions suggest that the resistances follow a Mott variable-range hopping (VRH) law below 0.05 K. The low temperature magnetoresistance (MR) data showed changes of less than ±12 % of the zero field resistance values in fields up to 10 T. Fits using the wave function shrinkage and the forward interference models gave only fair agreement with the MR data.
KW - Activated and variable-range hopping (VRH) resistance laws
KW - Low temperature thermometry
KW - Magnetoresistance(MR)
KW - Speer carbon resistors
UR - http://www.scopus.com/inward/record.url?scp=18344387223&partnerID=8YFLogxK
U2 - 10.1007/s10909-005-4733-2
DO - 10.1007/s10909-005-4733-2
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AN - SCOPUS:18344387223
SN - 0022-2291
VL - 139
SP - 439
EP - 459
JO - Journal of Low Temperature Physics
JF - Journal of Low Temperature Physics
IS - 3-4
ER -