Transport properties of YBa2Cu3Ox /La0.67Sr0.33MnO3 nanostrips and YBa2Cu3Ox/La0.67Sr0.33MnO3/YBa2Cu3Ox nanojunctions

摘要

Ametallicferromagnet(F)inproximitywithasuperconductor(S)cantransportsupercurrentonalongdistancethroughconversionofopposite-spinsingletCooperpairs(CP)intoequal-spintripletCP(longrangetripletcomponent,LRTC),whicharenotbrokenbytheexchangeenergyofF.Theoptimalconditionsfortheconversionareyettobeclarified;however,itisacceptedthatthekeypointtothisprocessincludehighinterfacetransparencyandmagneticinhomogeneityattheSFinterface.TheaimofourpaperistostudySFnanostrips(lengthofabout1500nmandwidthdownto300nm)andlateralSFSnanojunctionsbasedonhighcriticaltemperatureYBa2Cu3Ox(YBCO)andhalf-metallicLa0.67Sr0.33MnO3(LSMO)thinfilms.WeappliedafocusedGa+ionbeam(FIB)forpatterningtheSFnanostrips,aswellaslateralSFSnanojunctions,bycreatingaslotinthenanostripafterremovingtheYBCOfilmintheslotalongalengthofabout200nm.ThetemperaturedependencesofthesamplesresistanceR(T)showcriticaltemperatureTCn≈89KoftheSFnanostrips;however,theSFSnanojunctionsatTTCnshowaresidualresistanceR100ΩcorrespondingtoadirtyLSMO(ρ≈10mΩcm)intheslot.TheLRTCwasnotobservedinourlateralSFSnanojunctionsuntilnow...