Role of quantum entanglement due to a magnetic impurity on current magnification effect in mesoscopic open rings

We study the current magnification effect in presence of exchange scatterin g of electron from a magnetic impurity placed in one arm of an open mesosco pic ring. The exchange interaction causes entanglement of electron spin and impurity spin. Earlier studies have shown that such an entanglement causes reduction or loss of interference in the Aharonov-Bohm oscillations leadin g to decoherence. We find however, that this entanglement, in contradiction to the naive expectation of a reduction in current magnification, leads to enhancement as well as suppression of the effect. We also observe addition al novel features like new resonances and current reversals.