Low frequency noise in La0.7Sr0.3MnO3 based magnetic tunnel junctions

摘要

Magnetic tunnel junctions based on manganites can exhibit a high tunneling magnetoresistance ratio due to the almost full spin polarization at the Fermi level. However, the performances of magnetic tunnel junction devices are also strongly linked to their noise characteristics. Here, we present a low frequency noise study on fully epitaxial La0.7Sr0.3MnO3/SrTiO3/La0.7Sr0.3MnO3/La0.66Sr0.33Mn0.995Ru0.005O3 tunnel spin valves with tunneling magnetoresistance ratios larger than 100%. We evidence non-conventional low frequency noise dependence on temperature related to the magnetic fluctuations and structural phase transitions in the structure. We present also a comparison with the low frequency noise exhibited in Fe/MgO/Fe magnetic tunnel junctions.