  Multiferroics with coplanar magnetic order are discussed in terms of a
superfluid condensate, with special emphasis on spin supercurrents created by
phase gradients of the condensate and the effect of external electric fields.
By drawing the analogy to a superconducting condensate, phenomena such as
persistent currents in rings, the Little-Parks effect, fluxoid quantization,
the Josephson-like effect through spin domain walls, and interference behavior
in a SQUID-like geometry are analyzed for coplanar multiferroics.
