Tunable magnetism on the lateral mesoscale by post-processing of Co/Pt heterostructures

Controlling magnetic properties on the nm-scale is essential for basic research in micro-magnetism and spin-dependent transport, as well as for various applications such as magnetic recording, imaging and sensing. This has been accomplished to a very high degree by means of layered heterostructures in the vertical dimension. Here we present a complementary approach that allows for a controlled tuning of the magnetic properties of Co/Pt heterostructures on the lateral mesoscale. By means of in-situ post-processing of Pt- and Co-based nano-stripes prepared by focused electron beam induced deposition (FEBID) we are able to locally tune their coercive field and remanent magnetization. Whereas single Co-FEBID nano-stripes show no hysteresis, we find hard-magnetic behavior for post-processed Co/Pt nano-stripes with coercive fields up to 850 Oe. We attribute the observed effects to the locally controlled formation of the CoPt L1$_{0}$ phase, whose presence has been revealed by transmission electron microscopy.Comment: Accepted for publication in Beilstein J. Nanotechno

Superconducting Proximity Effect in Crystalline Co and Cu Nanowires

Superconducting proximity effect is investigated by electrical resistance measurements in individual single-crystal Cu and polycrystalline Co nanowires in contact with a W-based floating inducer electrode (Tc= 5.2 K). Our analysis of the resistance drops shows that in both nanowires,(i)the superconducting proximity length ξ is of the order of 1μm at 2.4 K and (ii) its temperature dependencies can be fitted well to an expression of the form ξ(T)∝√ 1/Tin a wide temperature range, in good agreement with the theoretical predictions for ξ(T )in the diffusive limit. For the Co nanowire, dependencies of the spin-triplet ξ upon current and magnetic field are also reporte