Structural Properties of Co and CoFe Electrodes Forming a Magnetic Tunnel Junction

The M1/MgO/M2 trilayer tunnel magnetoresistance systems are studied by means of X-ray diffraction, NMR, and transmission electron microscopy techniques. As M1 and M2 electrodes we used Co, Fe, and CoFe layers. The growth mechanism and structural quality of both electrodes and of the epitaxial MgO barrier forming the magnetic tunnel junctions are experimen-tally examined. It is shown that the crystallographic coherence of magnetic tunnel junctions across the MgO barrier is significantly disturbed by imper-fect crystal structure of magnetic electrodes. The NMR results indicate a difference in short-range order between bottom and top electrodes. PACS numbers: 81.15.Hi, 68.65.Ac, 61.10.Nz, 76.60.Lz, 68.37.Lp 1