Superconducting switching due to triplet component in the Pb/Cu/Ni/Cu/Co${}_2$Cr${}_{1-x}$Fe${}_x$Al${}_y$ spin-valve structure

Abstract

We report the superconducting properties of the Co${}_2$Cr${}_{1-x}$Fe${}_x$Al${}_y$/Cu/Ni/Cu/Pb spin-valve structure which magnetic part comprises the Heusler alloy layer HA = Co${}_2$Cr${}_{1-x}$Fe${}_x$Al${}_y$ with a high degree of spin polarization (DSP) of the conduction band and the Ni layer of variable thickness. We obtained that the separation between the superconducting transition curves measured for the parallel ($\alpha =0^{\circ }$) and perpendicular ($\alpha =90^{\circ }$) orientation of the magnetizations of the HA and Ni layers reaches up to 0.5 K ($\alpha$ is an angle between the magnetization of two ferromagnetic layers). For all studied samples the dependence of the superconducting transition temperature $T_c$ on $\alpha$ demonstrates a deep minimum in the vicinity of the perpendicular configuration of magnetizations. This suggests that the observed minimum and the corresponding full switching effect of the spin valve is caused by the long-range triplet component of the superconducting condensate in the multilayer. Such a large effect can be attributed to a half-metallic nature of the HA layer which in the orthogonal configuration efficiently draws off the spin-polarized Cooper pairs from the space between the HA and Ni layers. Our results indicate a significant potential of the concept of the superconducting spin-valve multilayer comprising a half-metallic ferromagnet recently proposed by A. Singh et al., Phys. Rev. X 5, 021019 (2015) in achieving large values of the switching effect.

arXiv comment6 pages with 4 figures

References in corpus (9)

• Superconducting Spintronics
• Evidence for Triplet Superconductivity in a Superconductor-Ferromagnet Spin Valve
• Nonmonotonic critical temperature in superconductor/ferromagnet bilayers
• Superconducting triplet spin valve
• Full spin switch effect for the superconducting current in a superconductor/ferromagnet thin film heterostructure
• Half-Metallic Superconducting Triplet Spin Valve
• Triplet proximity effect in superconducting heterostructures with a half-metallic layer
• Boosting the superconducting spin valve effect in a metallic superconductor/ferromagnet heterostructure
• Isolation of proximity-induced triplet pairing channel in a superconductor/ferromagnet spin valve

Cited by in corpus (4)

• Superconducting spin-valve effect in heterostructures with ferromagnetic Heusler alloy layers
• Superconducting spin valve effect in the Co/Pb/Co heterostructure with insulating interlayers
• Expanding the operational temperature window of a superconducting spin valve
• Superconducting spin valve effect in Fe/Si${}_3$N${}_4$/Pb/Si${}_3$N${}_4$/Fe heterostructures