Room-temperature ferromagnetism in nanoparticles of superconducting materials

TL;DR

This study demonstrates that certain superconducting nanoparticles, including YBCO, NbN, and delta-MoN, exhibit room-temperature ferromagnetism, contrasting with their bulk forms and revealing potential for magnetic applications.

Contribution

It is the first to report room-temperature ferromagnetism in nanoparticles of various superconducting materials, expanding understanding of magnetic properties at the nanoscale.

Findings

Nanoparticles of YBCO show ferromagnetism at room temperature.

Bulk YBCO exhibits linear magnetization, not ferromagnetism.

Metal nitrides NbN and delta-MoN also show room-temperature ferromagnetism.

Abstract

Nanoparticles of superconducting YBa2Cu3O7-delta (YBCO) (Tc = 91 K) exhibit ferromagnetism at room temperature while the bulk YBCO, obtained by heating the nanoparticles at high temperature (940 degree C), shows a linear magnetization curve. Across the superconducting transition temperature, the magnetization curve changes from that of a soft ferromagnet to a superconductor. Furthermore, our experiments reveal that not only nanoparticles of metal oxides but also metal nitrides such as NbN (Tc = 6 - 12 K) and delta-MoN (Tc ~ 6 K) exhibit room-temperature ferromagnetism.