Abstract
Design conditions of the specific refrigerator is discussed, and a proto-type apparatus for the experiment was constructed. Gd disc of 20mm dia. ×10 or 20mm thickness was used and magnetized by step-promoting magnet with Sm-Co compound pole-pieces of (30mm)2×10mm t. It provides magnetic field of 4 to 6 kOe, and gives rise to T≤1.2K adiabatically on the Gd specimen. In order to obtain considerable low temeperatures, 4 or 6 Gd specimens were thermally connected via thermal switch in cascade series. The switch was operated by mechanical contact between high-conducting metal plates. At present, the stationary temperature difference through the cascade series was attained only to 0.46K, probably as due to poor conductance (KON≤0.2W/K) of the thermal switch.
