Study of [Co/Ni](111) superlattice-based structures for spintronics applications
Résumé
In a preceding study, we showed that magnetization in Co/Ni(111) superlattices grown by Molecular Beam Epitaxy is perpendicular for a Co thickness range between 0.2 and 3.5 ML. This system is particularly interesting to study spin transfer in devices since the critical currents are strongly decreased compared to devices with in-plane magnetization. In this context, we study magnetic characteristics, magneto-transport properties on Co/Ni(111) superlattices-based structures.
Firstly, using ferromagnetic resonance, we found that the damping constant in these Co/Ni(111) epitaxial is very small around 0.01. Also, the photoemission experiment showed that the spin polarization at the Fermi level is very high compared to bulk Co. These results make this system a very good candidate for spin transfer study. In a second time, the magneto-transport properties of [Co/Ni]/Au/[Co/Ni] spin valves structure were analyzed: a giant magnetoresistance effect of 1.5% was measured at room temperature. And finally, the domain wall propagation and pinning was studied in [Co/Ni] nanowires using transport measurement combined with Kerr microscopy experiment.
Our results demonstrated that the epitaxial [Co/Ni](111) superlattices are a promising candidate spintronics devices application.