{Gd44Ni22}: a gigantic 3d–4f wheel-like nanoscale cluster with a large magnetocaloric effect

A previously undiscovered gigantic 3d–4f wheel-like nanoscale cluster, {Gd 44 Ni 22 }, exhibits a large magnetocaloric effect (−Δ S m = 44.9 J kg −1 K −1 at 2.0 K for Δ H = 7 T).