Magnetization of small lead particles

TL;DR

This study measures magnetization in lead particles of various sizes, revealing a critical size below which superconductivity disappears, confirming theoretical predictions about size-dependent superconducting behavior.

Contribution

It provides direct experimental evidence of a critical particle size for superconductivity in lead, aligning with Anderson's criterion.

Findings

Superconductivity vanishes below a certain lead grain size.

A sharp disappearance of the Meissner effect is observed in small grains.

Results support the size-dependent superconductivity theory.

Abstract

The magnetization of an ensemble of isolated lead grains of sizes ranging from below 6 nm to 1000 nm is measured. A sharp disappearance of Meissner effect with lowering of the grain size is observed for the smaller grains. This is a direct observation by magnetization measurement of the occurrence of a critical particle size for superconductivity, which is consistent with Anderson's criterion.