The temperature and field dependences of the specific heat of single-crystal NdMnO-3 were investigated from 2K to 200K under different fields up to 8T.Corresponding to the Type-A antiferromagnetic (A-AF) phase transition in the Mn sub-lattice,the specific heat under zero field exhibited a sharp λ-shaped peak at about 85K,which was depressed and broadened and changed smoothly with the increase of magnetic field.But the entropy change due to the magnetic order is only 26% of the expected value,which might ari...