Tunnel magnetoresistance and Coulomb blockade in a planar assembly of cobalt nanoclusters embedded in TiO2
Résumé
Magnetic and magnetotransport properties of Co nanoclusters embedded in a TiO2 matrix grown by pulsed laser deposition have been studied. The results show a tunneling magnetoresistance associated with spin-polarized multiple quantum tunneling through the Coulomb energy barrier (Coulomb blockade effect). A shift between the fields at the magnetoresistance maxima and the coercive fields in the Coulomb blockade regime is observed. This shift decreases with increasing temperature and disappears when the thermal energy becomes stronger than the Coulomb blockade energy. (c) 2007 American Institute of Physics.