Heat Capacity Measurements on Some High-Temperature Superconductors Below 1 K byMeans of Two Non-Adiabatic Methods

摘要

The experimental setup and block diagrams of the equipment used are described.Heat conductivity measurements on some materials and systems that were important for the testing of the apparatus and for the construction of the supporting equipment are described. The development and testing of new types of thermometers, used in the later calorimetry experiments, is discussed. These thermometers appeared to play a crucial role in obtaining the accuracy of the results of the heat capacity and heat conductivity measurements. Research on radiation damage of some types of thermometers is addressed. The method and peripheral equipment developed and used for the heat capacity measurements are described. The measurements, as performed with the setup on magnetic superconductors, particularly on the 90 K superconductors on the REBa2Cu3O(7-delta) series are presented. To obtain more information about the behavior of the samples when using the non-adiabatic methods for the heat capacity measurements, the heat conduction of some of these materials was measured. Some interesting phenomena associated with the magnetic phase transitions are discussed.