Abstract
Within the state-of-the-art 3D Ginzburg–Landau (GL) formalism, we investigate the static features of the most sensitive SQUID-on-tip (SOT) device placed on the top of a nano-particle. The SOT sensor’s free energy, Cooper pair density, and screening current density in the loop are investigated for the nano-particle’s various placements and sizes. The dynamic aspects of the device, such as its voltage–current characteristics, are evaluated in the presence of transport current using the two-dimensional (2D) time-dependent GL formalism. The sensitivity of the SOT is examined using quantum oscillations of the device’s depairing current as a function of the nano-particle’s size and location. The location of the nano-particle at the device’s center and closer to the device’s loop is required for optimal SOT sensitivity.
Highlights
Magnetic field imaging at the nano-scale is highly challenging
We investigated the static characteristics of the SOT using the three-dimensional (3D) Ginzburg–Landau (GL) formalism and the dynamic properties using the 2D time-dependent Ginzburg–Landau (TDGL) formalism in the presence of applied transport current for the particle’s different locations and sizes
The black dashed line indicates the region of the lead’s contact with the loop. ∣ψ∣2 in the loop of the SOT is suppressed greater in the (d) DD and (a) DP cases due to the (f) higher screening current on that region. (f) Many screening currents are observed on both arms of the loop than the contact region of the leads. (e) The stability range of the Meissner state of the device is Δmg = 3.60, 4.80, 6.00, and 6.80 Hc2 in the case of DD, DP, DPS, and DLP, respectively
Summary
Magnetic field imaging at the nano-scale is highly challenging. In the numerous frontiers of science and nano-technology, another challenge is achieving the required sensitivity for detecting the magnetic moment of a single electron.. Due to the growing interest in this area of study, compassionate imaging methods of local magnetic fields at the nano-scale are fast evolving.. Superconducting quantum interference devices (SQUIDs) based on planar technology with lithographic or focused ion beam (FIB) patterning methods have the highest field sensitivity, they currently have a relatively low spatial resolution due to their loop diameter being typically several micrometers.. Interest in nano-SQUIDs is multi-dimensionally diversifying to overcome this constraint.. The primary challenge is to develop a nano-scale magnetic field sensor with a suitable shape and high field sensitivity.. In the numerous frontiers of science and nano-technology, another challenge is achieving the required sensitivity for detecting the magnetic moment of a single electron. Due to the growing interest in this area of study, compassionate imaging methods of local magnetic fields at the nano-scale are fast evolving. superconducting quantum interference devices (SQUIDs) based on planar technology with lithographic or focused ion beam (FIB) patterning methods have the highest field sensitivity, they currently have a relatively low spatial resolution due to their loop diameter being typically several micrometers. Recently, a susceptometer was created that combines a SQUID with a 600 nm pickup loop capable of scanning 300 nm above the sample surface. At the moment, interest in nano-SQUIDs is multi-dimensionally diversifying to overcome this constraint. The primary challenge is to develop a nano-scale magnetic field sensor with a suitable shape and high field sensitivity. Numerous works have been conducted to enhance the sensitivity of SQUIDs, with geometry or nano-patterning methods, for nano-particle investigation.
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