Josephson spin-valve realization in the magnetic nodal-line topological semimetal Fe${}_3$GeTe${}_2$

Abstract

Three-dimensional van der Waals ferromagnet Fe${}_3$GeTe${}_2$ (FGT) is regarded as a candidate for the magnetic topological nodal line semimetal. We investigate lateral electron transport between two 3~$\mu$m spaced superconducting In leads beneath a thick three-dimensional FGT exfoliated flake. At low 30~mK temperature, we observe Josephson supercurrent that exhibits unusual critical current $I_c$ suppression by the magnetic field $B$. The overall $I_c(B)$ pattern is asymmetric in respect to the B sign. We demonstrate, that the asymmetry is defined by the magnetic field sweep direction, so the $I_c(B)$ pattern is strictly reversed (as $B$ to $-B$ inversion) for the opposite sweeps. We also observe an interplay between maximum and minimum in $I_c(B)$ in normal magnetic fields, while there are fast aperiodic $I_c(B)$ fluctuations for the in-plane ones. These effects can not be expected for homogeneous superconductor-ferromagnet-superconductor junctions, while they are known for Josephson spin valves. The mostly possible scenario for Josephson spin valve realization in FGT is the misalignment of spin polarizations of the Fermi arc surface states and ferromagnetic FGT bulk, but we also discuss possible influence of spin-dependent transport between magnetic domains.

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Cited by in corpus (8)

• Gate-dependent non-linear Hall effect at room temperature in topological semimetal GeTe
• Interface superconductivity in a type-II Dirac semimetal NiTe${}_2$
• Andreev reflection for MnTe altermagnet candidate
• Evidence for surface spin structures from first order reversal curves in Co3Sn2S2 and Fe3GeTe2 magnetic topological semimetals
• Second-harmonic response as a tool to detect spin textures in magnetic nodal-line semimetal Fe${}_3$GeTe${}_2$
• Reentrant proximity-induced superconductivity for GeTe semimetal
• Fractional ac Josephson effect as evidence of topological hinge states in a Dirac semimetal NiTe2
• Josephson diode and spin-valve effects on the surface of altermagnet CrSb