  23Na NMR studies of the Na-K eutectic alloy embedded into porous glass with 7
nm pores showed that melting of Na2K confined nanoparticles is a continuous
process with smooth changes in the Knight shift of a narrow resonance line and
nuclear spin relaxation between those in the crystalline and liquid states. The
intermediate state which occurs upon melting is stable and more favorable than
the liquid state. The inverse freezing transformation can be sharp as at a
first order transition or continuous depending on the initial temperature of
cooling. The results suggest revision of theoretical predictions for the
melting and freezing transitions in confined geometry.
