Parallel magnetic field suppresses dissipation in superconducting nanostrips

Abstract

The motion of Abrikosov vortices in type-II superconductors results in a finite resistance in the presence of an applied electric current. Elimination or reduction of the resistance via immobilization of vortices is the "holy grail" of superconductivity research. Common wisdom dictates that an increase in the magnetic field escalates the loss of energy since the number of vortices increases. Here we show that this is no longer true if the magnetic field and the current are applied parallel to each other. Our experimental studies on the resistive behavior of a superconducting Mo0.79Ge0.21 nanostrip reveal the emergence of a dissipative state with increasing magnetic field, followed by a pronounced resistance drop, signifying a re-entrance to the superconducting state. Large-scale simulations of the threedimensional time-dependent Ginzburg-Landau model indicate that the intermediate resistive state is due to an unwinding of twisted vortices. When the magnetic field increases, this instability is suppressed due to a better accommodation of the vortex lattice to the pinning configuration. Our findings show that magnetic field and geometrical confinement can suppress the dissipation induced by vortex motion and thus radically improve the performance of superconducting materials.superconducting vortices parallel magnetic field Time-dependent GinzburgLandau simulation Abbreviations: TDGL simulation:Time-Dependent Ginzburg-Landau simulation ortex dynamics determines the electromagnetic responses of almost all practically important superconductors. Abrikosov vortices are created by the magnetic field penetrating a type-II superconductor, each carrying a single flux quantum surrounded by circulating supercurrents [1]. Understanding the electromagnetic properties of superconductors in applied magnetic fields is crucial for the majority of superconducting applications. If an electric current, I, is applied to the superconductor with a magnetic induction B, the associated Lorentz force FL = I B can induce motion of the vortices if it is greater than the vortex pinning force due to defects.[2] The vortex motion in turn leads to dissipation and breakdown of the zero-resistance state. Another practically important situation is when the magnetic field and the current are parallel, for example in force-free superconductnomena, [13,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] including flux cutting [19,30,33,34], helical normal/superconducting domains, [35,36] and helical vortex flow. [13,31] However, the vortex behavior responsible for the observed dissipation in parallel magnetic field is still under debate [14,28,30,31].All the above mentioned experiments and theories focus on macroscopic samples with dimensions much larger than the superconducting coherence length. On the other hand, when the dimensions of the sample become comparable to the superconducting coherence length, the subtle interplay of vortex lattice confinement and pinning may lead to new behavior. Here, we investigate this non-trivial problem...

Strong In-Plane Magnetic Field-Induced Reemergent Superconductivity in the van der Waals Heterointerface of NbSe2 and CrCl3

“…Theoretically, to the best of our knowledge, the nature of intriguing reemergent superconducting phase observed in the NbSe2/CrCl3 heterostructure in the in-plane magnetic field could be understood through the mechanisms of that (i) the disorder induced flux-pinning nature 35,36 ; (ii) the exchange field compensation effect 37,38 ; (iii) the triplet pairing SC induced by the enhancement of interfacial spin-orbit coupling 48,49 ; and (iv) the FFLO state 11,12 . intertwined with vortex and defects [53][54][55] . Therefore, the experimental observation of anisotropic reemergent superconducting phase is pointed to the nature of FFLO state, which is driven by the strong interfacial spin-orbit coupling in the NbSe2/CrCl3 heterostructure with close atomic arrangement in the presence of in-plane magnetic field 34 .…”

Negative magnetoresistance in thin superconducting films with parallel orientation of current and magnetic field

“…In a very recent experiment [21] a two times thicker MoGe film (d = 100nm) was studied and negative magnetoresistance was observed in the temperature interval T = 5.8 − 5.95K near T c 6.1K. Note that the effect was absent at T = 6K when the thickness of the film approached 2ξ(T ) (ξ(0) = 6nm in this experiment).…”

“…The calculations of δF are done only in the limit I I c (H) while in the experiment of Ref. [21] the current could approach I c (H) (in this case δF → 0).…”

Time-dependent Ginzburg-Landau simulations of superconducting vortices in three dimensions

“…We have focused on a rather simple system, a thin uniform film, under conditions reproducing our measurements (crossed alternating and constant magnetic fields), as well as to predict what would happen under certain conditions, paying attention to the motion of vortices. Interesting results on static 3D simulations of vortices in parallel magnetic field can be found in [27]. Application of the developed method to high frequency response of the vortex system related with microwave stimulated superconductivity can be found in [2,28].…”