Open AccessTUNNELING GIANT MAGNETORESISTANCE IN Fe-Al2O3 GRANULAR FILMS
Author(s) -
Tao Zhu,
Yinjun Wang
Publication year - 1999
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.48.763
Subject(s) - condensed matter physics , magnetoresistance , quantum tunnelling , materials science , magnetization , coulomb blockade , giant magnetoresistance , film plane , electrical resistivity and conductivity , sputtering , spin (aerodynamics) , magnetic field , thin film , physics , magnetic anisotropy , nanotechnology , voltage , thermodynamics , quantum mechanics , transistor
Tunneling giant magnetoresistance(TGMR) in Fe-Al2O3 granular films which were prepared by co-sputtering have been reported.MR ratio of the film with Fe volume fractions fV≈0.45 takes a maximum of 4.4% at room temperature when a magnetic field of 1T was applied parallel to the film plane,accompanying huge specific electrical resistivities of the order of 105 μΩ·cm.Field dependence of the MR is well described by the form proportional to the square of the magnetization of the film.Temperature dependence of the MR ratio of the film has also been investigated.The MR exhibits strong temperature dependence.The MR below 50K remarkably increases with decreasing temperature resulting in MR14.9% and 26% at 20 and 4.2Krespectively.The anomalous increase of the MR at low temperature seems to arise from the successive onset of higher-order processes of spin-dependent tunneling between large granules through intervening small ones with strong Coulomb blockade.