Oxidation states and the quality of lower interfaces in magnetic tunnel junctions: oxygen effect on crystallization of interfaces
2013 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 25, no 13, 135302- p.Article in journal (Refereed) Published
Lower interfaces in magnetic tunnel junctions (MTJs), which are the basic components in many spintronic devices such as magnetoresistive random access memories, have crucial effects on the performance of these devices. To obtain more insight into such interfaces, we have introduced an ultrathin sensor layer of Fe-57 at the interface between the lower electrode and the oxide barrier in selected MTJs. This allowed us to perform nuclear resonant scattering measurements, which provide direct information on the magnetic properties and quality of the interfaces. The application of nuclear resonant scattering to study interfaces in MTJs is a unique approach in the sense that it gives information at the atomic level, and specifically from the interface where the sensor layer is deposited. Samples with different tunnel barrier thicknesses and varied oxidation times in the preparation of this barrier have been studied. These show that oxidation can not only increase the magnetic hyperfine fields but also cause an interesting smoothing and crystallizing of the interface. Another interesting finding is the observation of boron diffusion into the lower part of the FeCoB lower electrode towards the Ta seed layer.
Place, publisher, year, edition, pages
2013. Vol. 25, no 13, 135302- p.
Room-Temperature, Synchrotron-Radiation, Magnetoresistance, Alloys, Reliability, Memory, Mram
IdentifiersURN: urn:nbn:se:kth:diva-120273DOI: 10.1088/0953-8984/25/13/135302ISI: 000315992900007ScopusID: 2-s2.0-84875157303OAI: oai:DiVA.org:kth-120273DiVA: diva2:614461
FunderSwedish Foundation for Strategic Research Swedish Research CouncilKnut and Alice Wallenberg Foundation
QC 201304042013-04-042013-04-042013-04-04Bibliographically approved