Performance improvement of a two-stage GM cryocooler by use of Er(Ni0.075Co0.925)2 magnetic regenerator material Original Research Article

A newly developed magnetic regenerator material Er(Ni0.075Co0.925)2, having high specific heat at temperatures from 10 to 20 K, has been tested inside the second regenerator of a two-stage GM cryocooler. Different working conditions have been examined: four Er(Ni0.075Co0.925)2/Pb material ratios, three displacer reciprocating speeds, and two cryocooler stroke lengths. In the best working conditions, the experimental results show a cooling power improvement up to 15% over the whole temperature range from 10 to 20 K compared to that of the same GM cryocooler employing only lead.