Evolution of entanglement between magnetic moments under interaction with tunneling current

We investigate the evolution of entanglement between two magnetic moments which are initially independent and interact with electron current tunneling through them. The magnetic moments may be nanomagnets, magnetic atoms or atom clusters with spins larger than \frac12\frac{1}{2}. The tunneling of electrons through two moments can be realized by equally coupling two leads (electron reservoirs) to them and applying bias voltage to the leads. In the sequential regime the effect of electron current on the entanglement is calculated fully quantum-mechanically by using extended scattering-matrix theory. It is found that under certain conditions the entanglement can be enhanced from zero to unity by applying the current. We investigate the dependence of the entanglement on the interaction strength and the value of the moments. We discuss the favorite conditions for the realization of entangling gates using such setup.