Spin superconductor in ferromagnetic graphene

We show a spin superconductor in ferromagnetic graphene as the counterpart to the charge superconductor in which a spin-polarized electron-hole pair plays the role of the spin 2(/2) "Cooper pair" with a neutral charge. We present a BCS-type theory for the spin superconductor. With the "London-type equations" of the super-spin-current density, we show the existence of an electric "Meissner effect" against a spatial varying electric field. We further study a spin superconductor/normal conductor/spin superconductor junction and predict a spin-current Josephson effect.