Study of vortex dynamics in an a-MoGe thin film using low-frequency two-coil mutual inductance measurements

Abstract

We extract the vortex lattice parameters using low-frequency two-coil mutual inductance measurements in a 20-nm-thick superconducting a-MoGe thin film. We fit the temperature dependence of ac penetration depth in the mixed state using a model developed by Coffey and Clem and demonstrate a procedure for extracting vortex lattice parameters such as pinning constant, vortex lattice drag coefficient, and pinning potential barrier. We show that the extracted parameters follow the magnetic field variation expected for a weakly pinned 2-dimensional vortex lattice.

Low-frequency electrodynamics in the mixed state of superconducting NbN and a-MoGe films using two-coil mutual inductance technique

“…Here, α L shows a nonmonotonic behaviour, where it displays a shallow minimum at around 10 kOe and then increases rapidly until 50 kOe. This is the signature of the onset of the peak effect, which has been discussed in earlier papers [35,66]. Here we also observe that the extracted η, which is typically associated with the BS flux flow viscosity, is 2-4 orders of magnitude larger than the BS estimate of the same, which can be calculated using ρ n ∼ 1.51 µΩ-m [57] and H c2 (2 K) ∼ 10.8 Tesla [66] and comes out as η BS (2 K) ∼ 1.47 * 10 −8 Ns m −2 .…”

“…The recipe for fitting the temperature variation of λ−2 using the CC model is similar to that used for NbN. However, as we have shown in an earlier work [35], in this case the exponential decay in the thermal smearing of the pinning landscape is more dominant than the prefactor. Therefore, we take the temperature variation of U and α L as α L ∼ α L0 e −T/T0 , U ∼ U 0 e −T/T0 .…”

“…Here, we employ a two-coil mutual inductance technique [31][32][33][34] to measure the complex penetration depth, λ, in the mixed state of the superconductor, and analyse the data using established theoretical models of vortex dynamics. An earlier study [35] on a-MoGe showed that while these models can explain the temperature and magnetic field dependence of the real part of λ−2 (the inductive response), they fail to explain the imaginary part of λ−2 (the dissipative response). In this paper, we show that a consistent description of both the inductive and dissipative response is obtained both in the strong and the weak pinning limit only when the value of η is taken to be several orders of magnitude larger than the conventional estimate obtained from Bardeen-Stephen (BS) theory [36,37].…”

Assemblies of Coaxial Pick-Up Coils as Generic Inductive Sensors of Magnetic Flux: Mathematical Modeling of Zero, First and Second Derivative Configurations

“…Obviously, the PUCs-based inductive sensors can be easily fabricated and are flexibly adjustable to the needs of every experiment at a practically negligible cost. This is why they have been used in a wide range of experimental studies on the properties of magnetic and superconducting materials, either in the form of a single PUC or two PUCs, with dimensions adjusted to the size of each sample [30][31][32][33][34][35]. Also, 3D magnetic field sensors based on planar PUCs that can be fabricated relatively easily have been studied by simulations and numerical analyses [36]; single PUC magnetic field sensors, without and with a core for plasma-based and power-cable applications have been reported so far [37,38], and single PUCs have been incorporated in LC resonators for the nondestructive evaluation of materials [39].…”