Low Temperature Thermometers Research Articles

Low-temperature thermometer using sputtered ZrN x thin film

A thin film thermometer using sputtered zirconium nitride has been investigated as a low-temperature thermometer. This film deposited on a sapphire substrate can be used to measure a wide temperature range from 1 to 300 K with reasonable sensitivity within a fast response time. The thermometer sensitivity can be altered by changing fabrication conditions. Moreover, the thermometer is almost insensitive to magnetic fields. The temperature error in a magnetic field of 6 T is less than 10 mK at 4.2 K.

Thick-film resistive temperature sensors

This paper discusses thick-film resistive temperature sensors investigated at the Technical University of Wroclaw. The technology and electrical properties of resistance temperature detectors, thermistors, low-temperature thermometers and heating elements are presented. The R(T) curve of chosen air-fireable Ni - P based films agrees with Ni wire. The initially aged thermistors from the system can operate in the range from room temperature up to 673 K. The commercial thick-film resistors modified by the negative TCR drivers (e.g. powder) are fully suitable for low-temperature measurements in the range from 20 to 100 K. The integrated gas sensors need heaters because temperature influences their sensitivity, selectivity and response time. The thick-film compatible system based on commercially available resistive and conductive inks allows continuous long-term electrical heating of the sensor up to 673 K. The admissible operating temperature is much higher for the heaters made from conductive inks; for example fritless platinum heaters are satisfactory up to 1073 K.

Design of RuO 2-based thermometers for the millikelvin temperature range

RuO 2-based thick film resistors (TFRs) were designed for use as low temperature thermometers in the millikelvin temperature range. The R- T characteristics and sensitivities of these thermometers below 1 K are comparable with germanium thermometers usually used in this temperature range. However, their low electrical resistance and their sensitivity are opposing properties which put certain technological limitations on their design. The temperature dependence of the resistance of RuO 2 sensors at the lowest temperatures investigated can be adequately described in terms of a variable-range hopping mechanism.

On the thermodynamic accuracy of the ITS-90: platinum resistance thermometry below 273 K

An analysis of the resistance-temperature relationship for six low-temperature platinum resistance thermometers is carried out to determine the thermodynamic accuracy of the ITS-90 below 273 K. The use of smooth thermodynamic functions in a model equation for platinum resistance indicates that there is a significant deviation of the ITS-90 from thermodynamic values over the range 80 K to 270 K. The deviation is consistent with recent results in acoustic and gas thermometry, namely around 10 mK at 150 K. For this reason a re-evaluation of the existing thermodynamic data on the temperature scale appears warranted.

Heat capacity of thick-film resistor thermometers and pure RuO 2 at low temperatures

The heat capacity of commercial thick-film chip resistors has been measured in the temperature range 0.1–2K. Three different types of resistors used as low temperature thermometers were investigated. The heat capacity of all samples shows a Schottky-type anomaly with the maximum at 0.4K amounting to 1μJ K −1 for the largest unit. We also report the data on the specific heat of a thermometer component, RuO 2, and show that it has no anomalous behaviour. The peak in heat capacity of these resistors puts limitations on using them as thermometers for low temperature calorimeters.

Thick platinum films as low temperature thermometers

Resistance measurements of thick platinum films between 4.2 and 300 K are reported. The thick films were prepared by standard screen-printing techniques. The properties of the films make them suitable for low temperature thermometry. In the temperature range 77–300 K experimental data are fitted using a quadratic fit with an error in temperature of less than 0.2%.

RuO 2-based thick-film resistors as high sensitivity thermometers for millikelvin temperatures

RuO 2-based thick-film resistors were designed for use as low temperature thermometers in the millikelvin temperature range. The thick films were printed in geometries providing 600 Ω and 2 kΩ units from 10 kΩ/□ and 100 kΩ/□ RuO paste, respectively. The sensitivities of these films below 1 K are comparable with germanium thermometers usually used in this temperature range and their reproducibilities are within 1% error in temperature.

Ceramic chip capacitors as low temperature thermometers

The results of thermal and magnetic field studies are reported for commercially available ceramic chip capacitors commonly used in hybrid microwave circuits. Capacitors with room temperature values of 51 and 45 pF have been investigated down to 4.2 K and in magnetic fields up to 9.0 T. The results show that these capacitors can be used as accurate, reproducible temperature sensors at low temperatures, especially in high magnetic fields. These capacitors also have the useful properties of small size, ease of mounting, ruggedness and low cost.

Granular Nix (SiO2)100−x thin films as low temperature thermometers

A series of granular Nix (SiO2)100−x thin films have been prepared by rf sputtering with nickel concentrations between 60 and 90 at. %. The temperature dependence of the resistance is strongly composition dependent. In films with Ni concentrations below 70%, the resistance increases as the temperature decreases, but shows a crossover to a weaker temperature dependence below about 1 K. The magnetoresistance of these materials is small and negative in applied magnetic fields up to 6 T. The temperature dependence of the resistance and the small magnetoresistance indicate that films with Ni concentrations near 66% may be useful for thermometry over a wide range of temperatures.

Thick film chip resistors for use as low temperature thermometers

We have measured the resistance and magnetoresistance of commercially produced thick film resistors in the range 80 K-15 mK and in fields up to 20 T. These resistors behave similarly to those produced by another manufacturer and characterized recently by a Japanese group. Between 2.5 and 0.1 K the resistance of a 1 kΩ resistor can be fit to R=A exp(B/T 1 4 ) . A 100 kΩ resistor appears to fit a similar expression between 1.6 and 6 K and fits a T −1 2 law from 8 to 80 K. These resistors are very stable upon thermal cycling, have a small magnetoresistance, and should be useful as thermometers over a wide temperature range.

Behaviour of thick film resistors (Philips type RC-01) as low temperature thermometers in magnetic fields up to 5 T

The properties of some RuO 2 thick film resistors, Philips type RC-01, have been studied between 15 mK and 4 K in magnetic fields up to 5 T. Resistors with room temperature resistance values between ≈ 1.0 and 4.7kΩ appear to have sufficient sensitivity, dR/RdT, for them to be used as secondary thermometers for temperatures < 4 K Thick film resistors have several advantages over carbon composition resistance thermometers which are used more generally, e.g. a better reproducibility, an easier method of mounting on metal surfaces and a lower heat capacity. However, in contrast to what has been published so far about thick film resistors from other manufactures, the type RC-01 shows a considerable magnetoresistance, which is of the same order as that found for carbon resistors.

Low-temperature semiconductor resistance thermometer with heat conductor

A 0.5–100 K GaAs thermometer with a toroidal element and a heat conductor improving the thermal contact and mechanical strength is described. At 4.2 K the reproducibility is 10 mK and the thermal resistance is about 104 KW−1 for P ≈ 10−6 W.

Low-temperature thermometry in high magnetic fields. V. Carbon-glass resistors

The characteristics of carbon-glass resistance thermometers for temperatures from 2.15 to 320 K and in magnetic fields of up to 19 T are described. The results from nine thermometers made from six different batches of raw material are combined to produce mean values that may be used to correct a ’’typical’’ thermometer at 19 T to within ±0.1% in temperatures between 30 and 320 K, and to within ±1% between 2.15 and 30 K. All nine sensors show a small orientation dependence of their magnetoresistance at 77 K; two out of four tested have an experimentally significant dependence at 4.2 K. The temperature error corresponding to the magnetoresistance of a miniature precision platinum resistance thermometer at 19 T is less than for carbon-glass sensors above 77 K. New recommendations are made for the optimum use of low-temperature thermometers in high magnetic fields.

Apparatus for graduation of low-temperature thermometers in the presence of strong magnetic fields

7. P. G. Strelkov, et al., Zh. Fiz. Khim., 28 (1954). 8. Vestrum et al., in: Low-Temperature Calorimeter [in Russian], Mir, Moscow (1971). 9. V. M. Malyshev, in: Theses of Papers of the Sixth All-Union Conference on Calorimetry [in Russian], Metsniereba, Tbilisi (1973). i0. V.M. Malyshev and E. L. Sorokin, Metrology and Measurement Techniques, No. ii (1973). ii. G. T. Furukawa et al., NSRDS, Nat. Bur. Stand., No. 18 (1968).

Comment on 'Magnetic-field-induced temperature error of some low-temperature thermometers' (by H. Alms, R. Tillmanns, S. Roth)

For original paper see ibid., vol.12, no.1, p.62 (1979). The author makes brief recommendations regarding the use of Ge thermometers and capacitance thermometers.

Magnetic-field-induced temperature error of some low-temperature thermometers

The effect of high magnetic fields (up to 18.4T) on germanium, platinum and carbon resistance thermometers and SrTiO3 capacitive thermometers has been investigated in the temperature range from 2-87K. Figures are presented which allow a crude estimate of the real temperature if these thermometers are read under high-field conditions.

A low-temperature thermometer for 1H, 19F, and 13C

A single sample is described which can be used with either proton, fluorine, or carbon resonance spectra to calibrate probe temperature down to -145°C. Calibration data are tabulated.

High Sensitivity Temperature Sensors at Low Temperatures

High sensitivity temperature sensors (0.5<-1/R·dR/dT<5) suitable for 1–10 K have been developed using n-type Si single crystals subjected to the thermal diffusion processes of phosphorus and to etching. They are very useful as low temperature thermometers and bolometers. Carbon film resistors developed as thermometers in a relatively weak magnetic field (up to 4 kOe) are described. They are also useful as temperature insensitive heaters in some cases.

The influence of a magnetic field on an AuMn resistor at low temperatures

Measurements of the magnetoresistance of an AuMn (0.9 at %) based low-temperature resistance thermometer were made at 4.2 K in a magnetic field up to 13.5 T and 2.8 K and 1.8 K in fields up to 4.2 T. The change in the scattering cross-section of the electrons by the manganese spins due to the magnetic field produces an important decrease (up to 50% at 10 T) of the resistivity. Experimental relationships for the temperature and magnetic field characteristics of the resistor are indicated

Low temperature thermometry in high magnetic fields. IV. Allen-Bradley carbon resistors (0.5–4.2 K)

The transverse magnetoresistance of six 1/8-W Allen-Bradley carbon resistors with nominal room temperature resistances of 2.7, 3.9, and 5.6 Ω was measured at various temperatures between 0.5 and 4.2 K in static magnetic fields up to 140 kG. Below 1.5 K, the magnetic field induced temperature errors of the resistors are small, less than 25%, and are very reproducible, i.e., ±0.8% in the case of the 2.7 Ω units. Hence, these resistors are useful as low temperature thermometers in strong magnetic fields.