论文信息 - Modulated‐bath calorimetry

Modulated‐bath calorimetry

A new high‐resolution ac calorimetric technique is described for measuring the absolute heat capacity of extremely small samples. The method uses a thermocouple as the weak link to the bath and modulates the temperature of the bath sinusoidally in time. This eliminates the need for a separate thermometer and heater on the sample while retaining the ability to make absolute measurements with minimal addenda. Results for a 2.9 μg sample of the superconductor Ba0.6K0.4BiO3 in a magnetic field of 60 kOe show a jump at Tc=21 K, which is above the noise level of ∼2 parts in 104.

J. Graebner

[1] Rupp,et al. Density of states and isotope effect in BiO superconductors: Evidence for nonphonon mechanism. , 1988, Physical Review Letters.

[2] Salamon,et al. Measurement of the specific heat anomaly at the superconducting transition of YBa2Cu3O7- delta. , 1987, Physical review. B, Condensed matter.

[3] Golding,et al. Solid H2 in a-Si:H at low temperatures. , 1985, Physical review. B, Condensed matter.

[4] W. L. Mcmillan,et al. Metal-Insulator Transition in Disordered Germanium-Gold Alloys , 1981 .

[5] A. Anderson,et al. Calorimetry below 1 K: The specific heat of copper , 1974 .

[6] R. Howard,et al. Heat Capacity Measurements on Small Samples at Low Temperatures , 1972 .

[7] M. Salamon. Specific Heat of CoO near T N : Anisotropy Effects , 1970 .

[8] G. Seidel,et al. Steady-State, ac-Temperature Calorimetry , 1968 .

[9] D. W. Osborne,et al. Calibration and Use of Germanium Resistance Thermometers for Precise Heat Capacity Measurements from 1 to 25°K. High Purity Copper for Interlaboratory Heat Capacity Comparisons , 1967 .

[10] R. W. Hill,et al. LXVIII. The specific heat of beryllium at low temperatures , 1953 .

[11] J. C. Jaeger,et al. Conduction of Heat in Solids , 1952 .

[12] S. M. Dockerty. THE SPECIFIC HEAT OF COPPER FROM 30° TO 200° K. , 1937 .

[13] D. Murphy,et al. Growth and structural characterization of superconducting Ba1–xKxBiO3 single crystals , 1988, Nature.