Equivalent circuit model for the electrical analysis of a spin bipolar transistor

An equivalent circuit model for the switching performance of a spin bipolar transistor composed of a nonmagnetic metal film (N) sandwiched between two ferromagnetic metal films (F1 and F2) is suggested. The 'ON' or 'OFF' operation of this equivalent circuit model is simulated depending on the orientation of the magnetization of F1 and F2 rather than on the strength of the external magnetic field. Changing the coupling coefficient, by tuning the ratio of two inductances (L1 : L2) like a transformer and a parallel variable resistance R4 connected to L2 at the collector region, one can explain the magnetic resistance ratio based on the orientation of spin-polarized electrons. The simulation results show that the electrical performance is consistent with the physical operation of the spin bipolar transistor.