Oscillations of the Curie temperature and interlayer exchange coupling in magnetic trilayers

摘要: The onset of long-range magnetic order in exchange-coupled epitaxial Co/Cu/Ni trilayers, 2--4 monolayers (ML) each, on Cu(001) is studied by element-specific x-ray circular dichroism between 30 and 300 K ultrahigh vacuum. Oscillations the enhancement ordering temperature Ni $(\ensuremath{\Delta}{T}_{\mathrm{Ni}})$ more than 40 are measured as a function interlayer exchange interaction varying spacer thickness. Below Cu thickness 2.3 ML antiferromagnetic coupling measured. period, phase, amplitude $\ensuremath{\Delta}{T}_{\mathrm{Ni}}$ oscillations excellent agreement with theoretical prediction for short- long-period coupling.