Superconductor Wire Critical Current Density Measurement via Magnetization Loss

Solution Overview

Problem

Measuring critical current density in superconductor wires is challenging due to current distribution disparities during electrical current application, which can damage samples and hinder the evaluation of superconductor wire characteristics.

Innovation Solution

A method involving the application of an external magnetic field to superconductor wires to measure magnetization loss, normalizing and differentiating this loss to calculate the fully-penetration magnetic field, and subsequently determining the critical current density using the Brandt's strip model equation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electrical current is applied to measure critical current density, then measurement data can be obtained, but current distribution disparities occur causing sample damage

Engineering Contradiction:

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent uses magnetic field as an intermediary to indirectly measure critical current density. Instead of applying current directly to the sample, a magnetic field is applied and the resulting magnetization loss is measured. This intermediary approach allows obtaining measurement data without the harmful direct current application that causes sample damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the electrical measurement system with a magnetic measurement system. By substituting electrical current application with magnetic field application and measuring magnetization loss instead of electrical properties, the method eliminates the current distribution problems while maintaining measurement capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If electrical current is applied to measure critical current density, then measurement can be performed, but current distribution into each wire becomes disproportionate

Engineering Contradiction:

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The magnetic field serves as an intermediary that uniformly interacts with all wires in the bundle without causing disproportionate current distribution. The magnetic field penetrates the sample uniformly, and the magnetization loss measurement reflects the collective response of all wires, eliminating the current distribution uniformity problem.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

By replacing the electrical current application method with magnetic field application, the patent eliminates the fundamental issue of disproportionate current distribution. The magnetic measurement system inherently provides uniform interaction with all wires, making the measurement process easier and more reliable.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If magnetic field method is used to measure critical current density, then sample damage is prevented, but measurement complexity increases

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

While the measurement principle changes from electrical to magnetic, the overall system complexity is managed by using standard magnetic measurement equipment. The substitution of electrical current application with magnetic field application and voltage measurement maintains a relatively simple experimental setup while achieving reliable, non-destructive measurements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables the estimation of critical current density without physically applying current to the superconductor wires, preventing sample damage and providing accurate measurements with minimal error, as demonstrated by the method's ability to match physically measured values within an error range of less than 5% for most samples.

Implementation Method 1

measuring a magnetization loss of the superconductor wires, according to the application of the external magnetic field

Methodology Applied

Scientific EffectMagnetization loss: Magnetic Hysteresis

Data Source

PatentUS8788227B2Measuring method of critical current density of superconductor wires using measurement of magnetization loss

Publication Date: 2014.07.22

AI summary

A method for measuring critical current density of superconductor wires according to the present invention is characterized in that it includes: (a) applying an external magnetic field to the superconductor wires, (b) measuring a magnetization loss of the superconductor wires according to the application of the external magnetic field, (c) normalizing the measured magnetization loss, and then calculating a fully-penetration magnetic field of the superconductor wires according to the normalized magnetization loss, (d) calculating a critical current density of the superconductor wires according to the calculated fully-penetration magnetic field. Therefore, the critical current density of parallel superconductor wires such as stacked superconductor wires may be measured without applying current to the superconductor wires directly.