Structural comparison between MgO/Fe(001) and MgO/Fe(001)–p(1×1)O interfaces for magnetic tunneling junctions: An Auger electron diffraction study

• Published in: Applied surface science Vol. 305; pp. 167 - 172
• Main Authors: Cantoni, M., Boseggia, S., Petti, D., Cattoni, A., Bertacco, R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.06.2014
• Subjects: Auger electron diffraction; Background subtraction; Fe–p(1 × 1); Iron; Magnesium oxide; Magnetic tunneling junction; Magnetic tunneling junction; Iron; Auger electron diffraction; Background subtraction; Fe–p(1×1); Magnesium oxide
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2014.03.032

•We study MgO thin films on Fe(001) and Fe(001)–p(1×1)O for MTJ applications by AED.•Simulations are performed for calculating the AED pattern for the two structures.•The structural order of MgO is essentially the same in the two structures.•The seed layer, Fe or Feox, affects only the first two MgO layers at the interface.•Besides Fe(001), Fe–p(1×1)O is a good candidate as bottom layer for MgO-based MTJs.•A method for subtracting the experimental background from AED spectra is presented. Magnetic tunnel junctions based on MgO(001) barriers and ferromagnetic electrodes, such as Fe/MgO/Fe, represent a very popular and widely investigated subject in the field of spin-electronics because of the large values of magnetoresistance shown by these systems. In this paper, the structural properties of MgO thin films grown onto Fe(001) and MgO/Fe(001)–p(1×1)O surfaces, with MgO thickness ranging from 2 to 14 equivalent monolayers, have been investigated by means of Auger electron diffraction. The structural order and the crystal quality of the MgO films result practically independent from the template, the latter being either the clean Fe(001) surface or the oxidized Fe(001)–p(1×1)O one. This is confirmed by numerical simulations, showing that, apart from the first two MgO layers close to the interface, the structure is unaffected by the choice of the starting surface. By a structural point of view, we can conclude that Fe(001)–p(1×1)O is a good candidate for the role of bottom electrode for the realization of MgO-based magnetic tunnelling junctions, also considering its higher chemical stability and reproducibility if compared to the clean Fe(001) surface.