A cryogenic refrigerator includes a regenerative heat exchanger material in thermal contact with a working gas including a tin-antimony (Sn—Sb) alloy or a tin-gallium (Sn—Ga) alloy in at least one cooling stage. The re-generative heat exchanger material can include an Sn—Sb-M alloy, with M including at least one element selected from the group consisting of Bi, Ag, Ge, Cu, La, Mg, Mn, Nd, Ni, Pd, Pt, K, Rh, Sm, Se, S, Y, Fe, In, Al, Ce, Dy, Cd, Ti, Au, P, Pr, Yb and Zn. The cryogenic refrigerator can include a Gifford-McMahon refrigerator, a pulse tube refrigerator, or a Stirling refrigerator. A cryopump includes cryopanels adapted to condense or adsorb gases and a cryogenic refrigerator.