Short-range correlations in the magnetic ground state of Na4Ir3O8

TL;DR

This study investigates the magnetic ground state of Na4Ir3O8, revealing a short-range, frozen magnetic state at low temperatures that differs from a quantum spin liquid, driven by disorder or quantum fluctuations.

Contribution

It provides the first comprehensive experimental characterization of the inhomogeneous magnetic ground state in Na4Ir3O8 using multiple measurement techniques.

Findings

Development of a short-range, frozen magnetic state below 6 K

Persistence of quasi-static spin correlations down to 20 mK

Inhomogeneous magnetic ground state driven by disorder or quantum fluctuations

Abstract

The magnetic ground state of the hyper-kagome lattice in Na4Ir3O8 is explored via combined bulk magnetization, muon spin relaxation, and neutron scattering measurements. A short-range, frozen, state comprised of quasi-static moments develops below a characteristic temperature of T_F=6 K, revealing an inhomogeneous distribution of spins occupying the entirety of the sample volume. Quasi-static, short-range, spin correlations persist until at least 20 mK and differ substantially from the nominally dynamic response of a quantum spin liquid. Our data demonstrate that an inhomogeneous magnetic ground state arises in Na4Ir3O8 driven either by disorder inherent to the creation of the hyper-kagome lattice itself or stabilized via quantum fluctuations.