The long-range spin-triplet supercurrent transport is an interesting phenomenon in the superconductor/ferromagnet () heterostructure containing noncollinear magnetic domains. Here we study the long-range superharmonic Josephson current in asymmetric junctions. It is demonstrated that this current is induced by spin-triplet pairs  −  or  +  in the thick layer. The magnetic rotation of the particularly thin layer will not only modulate the amplitude of the superharmonic current but also realise the conversion between  −  and  + . Moreover, the critical current shows an oscillatory dependence on thickness and exchange field in the layer. These effect can be used for engineering cryoelectronic devices manipulating the superharmonic current. In contrast, the critical current declines monotonically with increasing exchange field of the layer, and if the layer is converted into half-metal, the long-range supercurrent is prohibited but still exists within the entire region. This phenomenon contradicts the conventional wisdom and indicates the occurrence of spin and charge separation in present junction, which could lead to useful spintronics devices.

Multilayers of [Co∕Pt]20, with tCo∕tPt≐7 and the period Λ in the range of 0.27–0.69nm, and [Co(0.46nm)∕Pt(0.07–0.14nm)]20 have been prepared by sputtering at low deposition rates and a high Ar pressure of 7.8Pa. Structure and magnetic properties were characterized by x-ray diffraction, transmission electron microscopy, magnetometry measurements, and magnetic force microscopy. Column structure, coherent stacking of Co and Pt layers, and small grains have been observed. The average atomic interplane distance d111 changes with the constituent layer thickness. In the first series of Co∕Pt multilayers, the out-of-plane coercivity gradually increases to reach a maximum, with the bilayer period increasing from 0to0.58nm, and decreases with further increasing period. For the second series, the out-of-plane coercivity increases to reach a maximum of 6.5kOe with tPt increasing from 0.07to0.13nm and decreases with further increasing tPt. In order to explain the strong magnetic perpendicular anisotropy, the magnetoelastic energy of CoPt alloy layers must be taken into account.

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Gate-tunable spin-resolved scattering through a Rashba spin–orbit (SO) coupling graphene barrier is considered theoretically by using a mode-matching method. In this structure, we investigate the dependence of the tunnelling transmission probability on the spin orientation of the incident electron. It is found that the difference of the transmission probability for opposite spin orientations exhibits considerable incident-angle-dependent features when both gate voltage and Rashba SO coupling in the barrier region are present. The difference is adjustable by the gate voltage. More specifically, we find that the sign of spin polarisation of conductance can switch from positive to negative by adjusting the electric potential at any Rashba SO coupling. These results can provide an efficient way to design graphene spintronic devices without the need for ferromagnets.