Strong Enhancement of the Tunneling Magnetoresistance by Electron Filtering in an Fe/MgO/Fe/GaAs(001) Junction

作者：Autes G^*; Mathon J; Umerski A

来源：Physical Review Letters, 2010, 104(21): 217202.

DOI：10.1103/PhysRevLett.104.217202

Calculations of the tunneling magnetoresistance (TMR) of an epitaxial Fe/MgO/Fe tunneling junction attached to an n-type GaAs lead, under positive gate voltage, are presented. It is shown that for realistic GaAs carrier densities the TMR of this composite system can be more than 2 orders of magnitude higher than that of a conventional Fe/MgO/Fe junction. Furthermore, the high TMR is achieved with modest MgO thicknesses and is very robust to disorder at the Fe/GaAs interface and within the GaAs layer itself. The significant practical advantage of this system is that huge TMRs should be attainable for junctions with modest resistances. For a GaAs carrier density of 10(19) cm(-3) the system is calculated to have a TMR in excess of 10 000% but its resistance is equivalent to that of a conventional Fe/MgO/Fe junction with only 6-7 at. planes of MgO.

• 出版日期2010-5-28