  We report the first numerical prediction of a "spin microemulsion" -- a phase
with undulating spin domains resembling classical bicontinuous
oil-water-surfactant emulsions -- in two-dimensional systems of spinor
Bose-Einstein condensates with isotropic Rashba spin-orbit coupling. Using
field-theoretic numerical simulations, we investigated the melting of a
low-temperature stripe phase with supersolid character and find that the
stripes lose their superfluidity at elevated temperature and undergo a
Kosterlitz--Thouless-like transition into a spin microemulsion. Momentum
distribution calculations highlight a thermally broadened occupation of the
Rashba circle of low-energy states with macroscopic and isotropic occupation
around the ring. We provide a finite-temperature phase diagram that positions
the emulsion as an intermediate, structured isotropic phase with residual
quantum character before transitioning at higher temperature into a
structureless normal fluid.
