Mn5Ge3 exchange couplings (Jij) 3

Mn5Ge3 (P6_3/mcm, a=7.194, c=5.061 Å) — known ferromagnet with Tc ≈ 298 K, used as a validation case for Curie temperature prediction routes.

TB2J exchange couplings on Mn5Ge3 vs the Renmin University group's single-crystal critical behavior (Tc 300.29 K, beta 0.336, J(r)~r^-4.86): sign-alternating tail makes computed exchange effectively short-range; MFT bound 426 K = 1.42x measured.