Spin accumulation in FSF single electron transistor

The concept of spin accumulation has paved the way for future spin-based devices with important applications in information storage and quantum computing. Spin accumulation induced pair breaking in superconductor attributes to the conductance increase in ferromagnet-superconductor-ferromagnet single electron transistors when the magnetization of the two ferromagnetic leads change from parallel to antiparallel configurations. From theoretical simulation, it is found that the Meservey-Tedrow effect also causes a similar conductance change since the magnetic field changes the energy spectrum of the quasiparticles. Therefore, it is crucial to distinguish the two effects in the experiment. A key feature of the Meservey-Tedrow effect is that the conductance change shows opposite sign under reverse bias. Based on this, a transport measurement through double tunnel junctions is setup with proper bias configuration, thus separating the two effects and demonstrating that spin accumulation is attained.