Lattice-mismatch-induced granularity in CoPt-NbN and NbN-CoPt superconductor-ferromagnet heterostructures: Effect of strain - Condensed Matter > SuperconductivityReport as inadecuate




Lattice-mismatch-induced granularity in CoPt-NbN and NbN-CoPt superconductor-ferromagnet heterostructures: Effect of strain - Condensed Matter > Superconductivity - Download this document for free, or read online. Document in PDF available to download.

Abstract: The effect of strain due to lattice mismatch and of ferromagnetic FMexchange field on superconductivity SC in NbN-CoPt bilayers is investigated.Two different bilayer systems with reversed deposition sequence are grown onMgO 001 single crystals. While robust superconductivity with high criticaltemperature T c ~ 15.3 K and narrow transition width DelT c ~ 0.4 K is seenin two types of CoPt-NbN-MgO heterostructures where the magnetic anisotropy ofCoPt is in-plane in one case and out-of-plane in the other, the NbN-CoPt-MgOsystem shows markedly suppressed SC response. The reduced SC order parameter ofthis system, which manifests itself in Tc, temperature dependence of criticalcurrent density J c T, and angular Phi variation of flux-flow resistivityRho f is shown to be a signature of the structure of NbN film and not a resultof the exchange field of CoPt. The Rho f H,T,Phi data further suggest thatthe domain walls in the CoPt film are of the Neel type and hence do not causeany flux in the superconducting layer. A small, but distinct increase in thelow-field critical current of the CoPt-NbN couple is seen when the magneticlayer has perpendicular anisotropy.



Author: R. K. Rakshit, S. K. Bose, R. Sharma, N. K. Pandey, R. C. Budhani

Source: https://arxiv.org/







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