Abstract: A method for preparing R5X4 alloy materials where R is a rare earth element selected from one or more of La, Ce, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu, Sc, and Y and X represents a non-rare earth alloying element such as silicon, germanium, tin, lead, gallium, indium and mixtures thereof. The method involves carbothermically reducing amounts of a rare earth element-containing oxide, an alloying element-containing oxide and/or alloying element in elemental or alloy form, and carbon at elevated temperature to form an R5X4 alloy material, which is melted, solidified, and optionally heat treated. Such a method provides an economical and efficient technique of configuring magnetic refrigerant, magnetostrictive and magnetoresistive alloys and products.

Abstract: A multi-stage cryocooler having a relatively low temperature stage to cool to less than about 15K and having a regenerator including a ductile intermetallic compound including one or more rare earth elements and one or more non-rare earth metals.