We study the effect of temperature on spin polarization in graphene-based ferromagnet insulator supercon- ductor (FIS) junctions, theoretically. Within the framework of BTK (Blonder Tinkham Klapwijk) theory we find that when is selected near to (where and represent Fermi energy and exchange field in the ferromagnet region) and temperature approaches to spin-polarization gets 100%. This case implies the spin-polarization is generated by just one spin species i.e. spin-up current, (). We also obtain a phase diagram − which distinguishes SAR (specular Andreev reflection) from NAR (normal Andreev reflection). Therefore, the proposed junction may be applied not only to create huge spin-polarization which is significant in spintronic-industry but also to discriminate SAR and NAR from each other which is important in fundamental condensed matter physics.
