The effect of inserting thin Co2MnAl layer into the Co2MnSi/MgO interface on tunnel magnetoresistance effect

We fabricated an epitaxially grown B2-ordered Co2MnAl Heusler alloy film by optimizing fabrication conditions, such as composition of the films and annealing temperature. Tunnel magnetoresistance (TMR) effect was investigated in Co2MnSi/Co2MnAl(0-1.0 nm)/MgO/CoFe magnetic tunnel junctions (MTJs). TMR ratio was enhanced by inserting a thin Co2MnAl layer at the Co2MnSi/MgO interface. The MTJ with Co2MnAl thickness of 0.5 nm exhibited the highest TMR ratio at 310 K and 10 K.

[1]  M. Shirai,et al.  Half-metallic behavior of Co2MnSi/Co2MnAl/MgO interface and its coherent tunneling conductance , 2010 .

[2]  A. Sakuma,et al.  Theoretical study on the stability of magnetic structures in the surface and interfaces of Heusler alloys, Co2MnAl and Co2MnSi , 2009 .

[3]  Yasuo Ando,et al.  Large tunnel magnetoresistance in magnetic tunnel junctions using a Co2MnSi Heusler alloy electrode and a MgO barrier , 2008 .

[4]  H. Ohno,et al.  Tunnel magnetoresistance of 604% at 300K by suppression of Ta diffusion in CoFeB∕MgO∕CoFeB pseudo-spin-valves annealed at high temperature , 2008 .

[5]  M. Katsnelson,et al.  Nonquasiparticle states in Co2MnSi evidenced through magnetic tunnel junction spectroscopy measurements. , 2007, Physical review letters.

[6]  H. Uchida,et al.  Coherent tunnelling conductance in magnetic tunnel junctions of half-metallic full Heusler alloys with MgO barriers , 2007, Journal of physics. Condensed matter : an Institute of Physics journal.

[7]  H. Kubota,et al.  Direct observation of half-metallic energy gap in Co2MnSi by tunneling conductance spectroscopy , 2006 .

[8]  Hitoshi Kubota,et al.  Huge Spin-Polarization of L21-Ordered Co2MnSi Epitaxial Heusler Alloy Film , 2005 .

[9]  S. Bluegel,et al.  Half-metallic ferromagnets for magnetic tunnel junctions by ab initio calculations , 2005, cond-mat/0506079.

[10]  A. Umerski,et al.  Theory of tunneling magnetoresistance of an epitaxial Fe/MgO/Fe(001) junction , 2001 .

[11]  Shoji Ishida,et al.  Search for Half-Metallic Compounds in Co2MnZ (Z=IIIb, IVb, Vb Element) , 1995 .