Enhanced room temperature magnetoresistance and spin injection from metallic cobalt in Co/ZnO and Co/ZnAlO films
2013 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, Vol. 5, no 9, 3607-3613 p.Article in journal (Refereed) Published
Co/ZnO and Co/ZnAlO films were prepared by depositing ultrathin cobalt layers and semiconductor layers on glass substrates at room temperature. The films consist of metallic Co particles, semiconductor matrix, and an interfacial magnetic semiconductor with the substitution of Co2+ for Zn 2+ in the ZnO lattice at the interface between Co particles and the semiconductor matrix. Large room temperature negative tunneling magnetoresistance was observed in the films. In addition, the magnetism and magnetoresistance were obviously enhanced by adding aluminum to the ZnO, and in one Co/ZnAlO sample, the room temperature negative magnetoresistance value reaches -12.3% at 18 kOe (compared with -8.4% of the corresponding Co/ZnO film) and the spin polarization of the tunneling electrons is about 37.5% which is characteristic of metallic Co. This enhancement of the tunneling spin polarization has been ascribed to the tunneling through an interfacial magnetic semiconductor, which causes the robust spin injection from cobalt metal into the semiconductors at room temperature resulting from the spin filter effect of the interfacial magnetic semiconductors.
Place, publisher, year, edition, pages
2013. Vol. 5, no 9, 3607-3613 p.
interfacial magnetic semiconductors, magnetoresistance, spin filtering, spin polarization, sputtering, Negative magneto-resistance, Room temperature magnetoresistance, Semiconductor layers, Semiconductor matrices, Spin filter effect, Tunneling magnetoresistance, Tunneling spin polarization, Interfaces (materials), Magnetic semiconductors, Substrates, Tunnelling magnetoresistance, Ultrathin films, Zinc oxide, Cobalt
IdentifiersURN: urn:nbn:se:kth:diva-134477DOI: 10.1021/am303276bISI: 000318839100018ScopusID: 2-s2.0-84877322798OAI: oai:DiVA.org:kth-134477DiVA: diva2:667151
QC 201311252013-11-252013-11-252013-11-25Bibliographically approved