Thermomagnetic vortex transport: Transport entropy revisited

Transport entropy, S d , defines both the thermal force, f th =− S d ∇ T , pushing a vortex along −∇ T in the Nernst effect and the thermal energy, th = S d T , transferred by a vortex in the Ettingshausen effect. All current theories associate the main contribution to S d with the electromagnetic energy of superconducting currents circulating around cores, F em ( T ). Using the universal relation between F em and magnetization (Dorsey A. T., Phys. Rev. B , 46 (1992) 8376 ) we extend our concept that magnetization currents do not transfer the thermal energy (Sergeev A. et al. , Phys. Rev. B , 77 (2008) 064501 ) and prove that supercurrents around cores neither produce the net force proportional to ∇ T , nor participate in the heat transport. Being consistent with the London concept and Onsager relation, our approach naturally explains the absence of the thermomagnetic effects in a system of Josephson vortices in SIS junctions. It elucidates the heat current definition and justifies the magnetization subtraction from the microscopically calculated energy (not heat) flux in the vortex liquid. The revised theory is in very good agreement with the measured entropy of Abrikosov's vortices and explains the nonmonotonic behavior of S d ( T ) with a maximum at ∼0.6 T c .