Parallel-Field Tunable SQUID Loop for Low Flux Noise
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Solution Overview
Problem
Superconducting circuits operating in strong magnetic fields face significant noise issues due to static and time-varying magnetic fields, which existing shielding and gradiometric designs fail to adequately address, leading to increased dissipation and flux noise.
Innovation Solution
A superconducting quantum interference device (SQUID) with a Josephson junction in a superconductive loop is oriented such that it can be tuned using a magnetic field parallel to the substrate, reducing flux noise by minimizing the effective surface area exposed to perpendicular fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical microscopy is used to characterize nanoscale features, then the imaging system can operate at room temperature with standard materials, but the resolution is insufficient to accurately characterize features below 50 nm
Solution Approach 1:
The patent replaces conventional optical microscopy with a scanning probe microscopy technique that uses a physical probe to scan the sample surface. This substitution of mechanical measurement for optical measurement enables sub-50 nm resolution by directly interacting with the sample surface topology rather than relying on light diffraction limits.
Solution Approach 2:
The patent introduces a specialized probe tip as an intermediary between the measurement system and the sample. This probe acts as a mediator that converts nanoscale surface features into detectable signals through controlled interactions, enabling high-resolution characterization without requiring complex optical systems.
2Measurement precision
If superconducting materials are used in the probe to achieve quantum sensing, then the measurement precision improves, but the probe requires cryogenic cooling and becomes more complex
Solution Approach 1:
The patent changes the temperature parameter of the probe materials to achieve superconducting states. By cooling the probe to cryogenic temperatures, the materials transition to superconducting phases that enable quantum sensing effects, dramatically improving sensitivity for detecting nanoscale magnetic and electric fields.
Solution Approach 2:
The patent exploits phase transitions of superconducting materials from normal to superconducting state through temperature control. This phase transition enables the probe to achieve enhanced quantum sensing capabilities, where the superconducting state provides extreme sensitivity for characterizing nanoscale features.
3Measurement precision
If the probe scans the entire sample surface to achieve comprehensive coverage, then the measurement completeness improves, but the time required increases significantly
Solution Approach 1:
The patent applies partial scanning by focusing the probe on specific regions of interest rather than scanning the entire sample surface. This selective approach achieves sufficient measurement coverage for characterizing critical nanoscale features while dramatically reducing the total scan time required.
Solution Approach 2:
The patent uses preliminary low-resolution scanning or other characterization methods to identify regions of interest before performing high-resolution scanning. This preliminary action enables the system to focus detailed probe scanning only on areas that require comprehensive characterization, reducing overall measurement time while maintaining completeness where needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces flux noise and allows for greater tolerance to strong magnetic fields, enabling more stable operation of superconducting circuits by using a parallel magnetic field for tuning, which induces less noise compared to perpendicular field tuning.
Implementation Method 1
superconducting quantum interference devices
Implementation Method 2
superconducting quantum interference devices
Implementation Method 3
scanning probe microscopy techniques
Data Source
Figure 1~2
Figure 3A~3C
Figure 4A~4C
AI summary
A system comprises a substrate (210) having a planar surface (212); a first magnet (240) configured to apply a first magnetic field parallel to the planar surface; a circuit (220) arranged on the planar surface; and a superconducting quantum interference device (230), SQUID, operably linked to the circuit. The SQUID comprises a Josephson junction (312) arranged in a superconductive loop (310). The superconductive loop includes a portion which extends perpendicular to the planar surface and is orientated such that the SQUID is tuneable by the first magnet. By allowing the SQUID to be tuned using a magnetic field which is parallel to the planar surface, a reduction in flux noise may be achieved. Also provided are a method of operating a SQUID, and a SQUID.