Thermal transport properties of graphene-based ferromagnetic/singlet superconductor/ferromagnetic junctions

We present an investigation of heat transport in gapless graphene-based ferromagnetic/singlet superconductor/ferromagnetic junctions. We find that unlike the uniform increase in the thermal conductance versus temperature, the thermal conductance exhibits intensive oscillatory behavior versus width of sandwiched s-wave superconducting region between the two ferromagnetic layers. This oscillatory form rises from interference of the massless Dirac fermions in graphene. Also we find that thermal conductance versus exchange field h displays a minimal value at h/E-f similar or equal to 1 within the low temperature regime where this finding demonstrates that propagating modes of the Dirac fermions in this value reach to their minimum numbers and verify the previous results for electronic conductance. We find that for thin widths of superconducting region, the thermal conductance versus temperature shows linear increment, i.e., Gamma proportional to T. At last we propose an experimental setup to detect our predicted effects. (C) 2010 American Institute of Physics. [doi:10.1063/1.3452364]