Note concerning the Mössbauer study of the order-disorder transformation in Ni3Mn

The Mossbauer study of stoichiometric Ni/sub 3/Mn shows that the transformation from the disordered to the ordered state proceeds by the classical first-order nucleation and growth process. Some Ni-Mn alloys are ferromagnetic in the ordered state and weakly ferromagnetic, or paramagnetic, in the disordered state. The difference is most pronounced near the composition Ni/sub 3/Mn. The samples were partially ordered by annealing in a helium atmosphere at 450 nif- C for 10 days. The spectrum left no doubt as to the transformation process. (C.E.S.)