Very low 1/f noise at room temperature in fully epitaxial Fe/MgO/Fe magnetic tunnel junctions

We report on room temperature 1/f noise in fully epitaxial Fe(45nm)/MgO(2.6nm)/Fe(10nm) magnetic tunnel junctions (MTJs) with and without carbon doping of the Fe/MgO bottom interface. We have found that the normalized noise (Hooge factor) asymmetry between parallel and antiparallel states may strongly depend on the applied bias and its polarity. Both types of MTJs exhibit record low Hooge factors being at least one order of magnitude smaller than previously reported.