Understanding the magnetic interaction between intrinsic defects and impurity ions in room-temperature ferromagnetic Mg1-xFexO thin films
2016 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 28, no 15, 156002Article in journal (Refereed) PublishedText
Understanding the nature and characteristics of the intrinsic defects and impurities in the dielectric barrier separating the ferromagnetic electrodes in a magnetic tunneling junction is of great importance for understanding the often observed 'barrier-breakdown' therein. In this connection, we present herein systematic experimental (SQUID and synchrotron-radiation-based x-ray absorption spectroscopy) and computational studies on the electronic and magnetic properties of Mg1-xFexO thin films. Our studies reveal: (i) defect aggregates comprised of basic and trimer units (Fe impurity coupled to 1 or 2 Mg vacancies) and (ii) existence of two competing magnetic orders, defect- and dopant-induced, with spin densities aligning anti-parallel if the trimer is present in the oxide matrix. These findings open up new avenues for designing tunneling barriers with high endurance and tunneling effect upon tuning the concentration/distribution of the two magnetic orders.
Place, publisher, year, edition, pages
2016. Vol. 28, no 15, 156002
magnetic-tunneling junction, intrinsic defects, room-temperature ferromagnetism, d0 magnetism, x-ray spectroscopy, density functional theory
IdentifiersURN: urn:nbn:se:kth:diva-185967DOI: 10.1088/0953-8984/28/15/156002ISI: 000373456900011PubMedID: 26987741ScopusID: 2-s2.0-84963815134OAI: oai:DiVA.org:kth-185967DiVA: diva2:926608
QC 201605092016-05-092016-04-292016-05-09Bibliographically approved