A SINGLE-CRYSTAL NEUTRON-SCATTERING STUDY OF LATTICE MELTING IN FERROELASTIC NA2CO3

We present the results of an extensive single-crystal neutron scatteri ng study of the ferroelastic phase transition in Na2CO3. This material has previously been demonstrated to undergo a continuous loss of long -range order at its ferroelastic transition, which is the phenomenon k nown as lattice melting. Fire show that our data are consistent with a special form of lattice melting where the long-range order appears to be destroyed in a two-dimensional sense, but is preserved in the thir d dimension.