Magnetic Regenerator Materials and 4 K Cryocoolers

Rui Li 

Cryogenics Division, Sumitomo Heavy Industries, Ltd. 

Magnetic regenerator material was innovatively developed in 1980’s. Since then, many efforts have been made in this field, which resulted in a great achievement on cryocooler development. In 1990’s, the world’s first 4 K Gifford-McMahon (4K-GM) cryocooler and the world’s first 4 K pulse tube cryocooler became commercially available. The birth of the 4 K cryocoolers made a revolutionary breakthrough in the cryogenic field below 10 K. In this paper the histories of the magnetic regenerator materials and the 4 K cryocoolers are reviewed. The major changes brought by the 4 K cryocoolers and the currently commercially-available 4 K cryocoolers will also be introduced. The next challenges about the magnetic regenerator materials and the 4 K cryocoolers will be mentioned finaly.