Heat transport of graphene-based normal metal–ferromagnetic barrier-superconductor junctions

• The exchange energy h has a strong effect on the thermal conductance oscillations.
• At α=π/4 the exchange energy has the highest effect on the thermal conductance κκ.
• Thermal conductance is strongly affected by the superconducting order parameter αα.
• The thermal conductance shows novel oscillations at α=π/4α=π/4.
• The h   affects the κκ versus temperature for both s- and d-wave superconductors.

In this paper, the effect of ferromagnetic barrier (FB) on the thermal conductance of graphene-based normal metal/ferromagnetic barrier/s- and d-wave superconductor junction has been studied theoretically. The results show that the exchange energy (h) in the ferromagnetic barrier has a strong effect on the amplitude, phase and period of the thermal conductance oscillations in terms of the FB length. Also, we have discussed novel thermal conductance oscillations in a graphene-based NFBS junction that happened for maximum superconducting orientation α=π/4. This finding is arisen from the quantum nature of interference between spin states, up and down quasiparticles in FB region. Interestingly, at α=π/4 the h has also the highest effect on the thermal conductance and by increasing the exchange energy h, the thermal conductance enhances at this angle. The exchange energy h also affects the thermal conductance as a function of temperature for both s- and d-wave superconductor. At last, we propose an experimental setup to detect our predicted effects.