Shot noise in magnetic double-barrier tunnel junctions

We calculate shot noise and the corresponding Fano factors in magnetic double-barrier tunnel junctions. Two situations are analyzed: (i) the central metallic layer is nonmagnetic while the external ones are ferromagnetic, and (ii) all of the metallic layers are ferromagnetic. In the latter case, the number of various magnetic configurations of the junctions is larger, which improves the functionality of such devices. The corresponding shot noise and Fano factor are shown to depend on the magnetic configuration of the junctions. The effect of spin relaxation in the central layer is also taken into account. The theoretical results are compared with experimental data on the shot noise in Fe/MgO/Fe/MgO/Fe structuresThis work is supported by the National Science Center in Poland as a research project in the years 2011–2014 and by the Polish National Center of Research and Development within the framework of the European project Era.Net.Rus “SpinBarrier” for the years 2012–2014. The work in Madrid has been supported by the Spanish MINECO (Grant No. MAT2012-32743, CONSOLIDER CSD2007-00010) and Comunidad de Madrid (Grant No. P2009/MAT-1726