Motion of a superconducting loop in an inhomogeneous magnetic field: a didactic experiment

TL;DR

This paper describes a didactic experiment demonstrating the motion of a superconducting loop in an inhomogeneous magnetic field, illustrating principles of Faraday's law and superconductivity through observed damped harmonic oscillations.

Contribution

It introduces a practical experiment that connects superconductivity, magnetic flux conservation, and harmonic motion, providing an educational tool for understanding these concepts.

Findings

Measured oscillation frequency matches theoretical predictions.

Damping constant varies with magnetic field strength as expected.

Experiment effectively demonstrates fundamental electromagnetic principles.

Abstract

We present an experiment conductive to an understanding of both Faraday's law and the properties of the superconducting state. It consists in the analysis of the motion of a superconducting loop moving under the influence of gravity in an inhomogeneous horizontal magnetic field. Gravity, conservation of magnetic flux, and friction combine to give damped harmonic oscillations. The measured frequency of oscillation and the damping constant as a function of the magnetic field strength (the only free parameter) are in good agreement with the theoretical model.