We studied the charge and spin currents in magnetic tunnel junctions in the presence of spin dynamics on the basis of a tight-binding scheme; the spin dynamics is assumed to be present only in one of the two ferromagnetic electrodes. The charge current is pumped by the dynamical spins having the form m1 m2, where mα (α =1, 2) denotes the direction of magnetization in the electrodes and m 1 represents the dynamic spin. In addition, three types of spin currents are induced by the dynamical spins. One of these spin currents has the form m1×m 2, whose coefficient is proportional to the product of the spin polarizations of both the electrodes. This term can possibly prevent magnetization switching, which is an effect that differs from both the Gilbert damping and spin transfer torque effects. Even in the absence of spin dynamics, the spin current exists in the form m1×m2. We have confirmed that the coefficient of this static term is equal to the effective exchange interaction between the two ferromagnetic electrodes.
ASJC Scopus subject areas
- Physics and Astronomy(all)