MgO/Fe(001) and MgO/Fe(001)-/p/(1X1)O interaces for magnetic tunneling junctions: a comparative study

The chemical, structural, and electronic properties of MgO/Fe001 and MgO/Fe001-p11O interfaces for magnetic tunnel junctions MTJs have been widely investigated by means of electron spectroscopy. In particular, we present a detailed analysis of the spin-resolved electronic structure above the Fermi level, carried out by spin-polarized inverse photoemission and absorbed current spectroscopy. The MgO barrier presents good crystallinity and sharp interfaces when grown both onto Fe001 and Fe001-p11O. Moreover, we find that the exchange splitting of unoccupied bands is essentially the same for the two MgO/Fe interfaces, even though it is different for the two starting surfaces, being larger in Fe001-p11O than in Fe001. Our findings indicate that Fe001-p11O is a good candidate for the realization of heterostructures for magnetic tunnel junctions because of its high chemical stability and reproducibility, as compared to clean Fe001.