Temperature and magnetic field dependence of thick-film resistor thermometers (Dale Type RC550)

We have measured the resistance of commercial thick-film chip resistors (Dale Type RC550, nominal resistance R = 500 Ω) as a function of temperature (8 mK ≤ T ≤ 10 K) and magnetic field B ≤ 7 T (for T ≥ 0.3 K) at different orientations between input current, main area and magnetic field. At 30 mK ≤ T < 10 K the temperature dependence of the resistance follows R = A exp (B/T^1/4) in agreement with published data for a 1 kΩ thick-film chip resistance. In contrast to previously published studies of similar resistors we measured a resistance that increases approximately linearly with field at T < 1 K and quadratically at higher temperatures. The sensitivity to magnetic fields decreases from (0.8 ± 0.1)% T^-1 at 0.3 K to 0.1% T^-1 above 2 K for B=1 T.