Heat Flow in Metals below 1 °K and a New Method for Magnetic Cooling

Abstract

Measurements have been made of the thermal conductivities of tin and tantalum both in the superconducting and normal states in the temperature range 0.2 deg to 1 deg K and experiments have been carried out on the question of thermal contact by heat flow through superconductors in this temperature range. The preliminary results of these experiments may be of interest in connection with two stage magnetic cooling methods, such as have been proposed for the study of nuclear paramagnetism and consequently are reported here. In addition the experiments have led to a convenient method for adiabatic magnetic cooling.