Heavy quasiparticles in the ferromagnetic superconductor ZrZn2

TL;DR

This study investigates the Fermi surface and quasiparticle masses in ZrZn2, revealing strong electron coupling and providing insights into its superconducting and magnetic properties.

Contribution

First direct measurement of quasiparticle effective masses in ZrZn2, confirming strong coupling to magnetic excitations or phonons.

Findings

Quasiparticle effective masses are enhanced by a factor of about 4.9.

Results are consistent with band structure calculations predicting exchange-split Fermi surfaces.

Insights into the mechanism of superconductivity and thermodynamic anomalies in ZrZn2.

Abstract

We report a study of the de Haas-van Alphen effect in the normal state of the ferromagnetic superconductor ZrZn2. Our results are generally consistent with an LMTO band structure calculation which predicts four exchange-split Fermi surface sheets. Quasiparticle effective masses are enhanced by a factor of about 4.9 implying a strong coupling to magnetic excitations or phonons. Our measurements provide insight in to the mechanism for superconductivity and unusual thermodynamic properties of ZrZn2.