Low noise all-oxide magnetic tunnel junctions based on a La$_{0.7}$Sr$_{0.3}$Mn$_{O3}$/Nb:SrTiO$_3$ interface

All-oxide magnetic tunnel junctions with a semiconducting barrier, formed by the half-metallic ferromagnet La$_{0.7}$Sr$_{0.3}$Mn$_{O3}$ and n-type semiconductor SrTi$_{0.8}$Nb$_{0.2}$O$_3$, were designed, fabricated, and investigated in terms of their magneto-transport properties as a function of a...

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Bibliographic Details
Published in:Applied physics letters 2017, Vol.110
Main Authors: Kurij, Georges, Solignac, Aurélie, Maroutian, T., Agnus, G., Guerrero, R., Calvet, L.E., Pannetier-Lecoeur, Myriam, Lecoeur, Philippe
Format: Article
Language:English
Subjects:
Physics
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Summary:All-oxide magnetic tunnel junctions with a semiconducting barrier, formed by the half-metallic ferromagnet La$_{0.7}$Sr$_{0.3}$Mn$_{O3}$ and n-type semiconductor SrTi$_{0.8}$Nb$_{0.2}$O$_3$, were designed, fabricated, and investigated in terms of their magneto-transport properties as a function of applied bias and temperature. We found that the use of the heavily Nb-doped SrTiO$_3$ as a barrier results in significant improvement in the reproducibility of results, i.e., of large tunnel magnetoresistance (TMR) ratios, and a spectral noise density reduced by three orders of magnitude at low temperature. We attribute this finding to a considerably decreased amount of point defects in SrTi$_{0.8}$Nb$_{0.2}$O$_3$, especially oxygen vacancies, compared with the conventional insulating SrTiO$_3$ barrier.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4977173