Collective magnetic state induced by charge disorder in the non-Kramers rare-earth pyrochlore Tb$_{2}$ScNbO$_{7}$

TL;DR

This study investigates how charge disorder influences magnetic states in the pyrochlore Tb$_{2}$ScNbO$_{7}$, revealing a spin glass transition coexisting with spin liquid correlations, suggesting a disorder-induced quantum spin liquid or topological glass phase.

Contribution

It provides detailed experimental evidence of disorder effects on magnetic frustration in a non-Kramers pyrochlore, proposing a new disorder-induced quantum spin liquid or topological glass phase.

Findings

Spin glass transition at 1 K observed

Coexistence of spin glass and spin liquid correlations

Charge disorder impacts magnetic ground state

Abstract

Geometrical frustration, as in pyrochlore lattices made of corner-sharing tetrahedra, precludes the onset of conventional magnetic ordering, enabling the stabilization of fluctuating spin states at low temperature. Disorder is a subtle ingredient that can modify the nature of these exotic non-ordered phases. Here, we study the interplay between disorder and magnetic frustration in the new pyrochlore Tb$_{2}$ScNbO$_{7}$ where the non magnetic site presents a charge disorder Nb$^{5+}$/Sc$^{3+}$. Its quantification with sophisticated diffraction techniques (electrons, X-rays, neutrons) allows us to estimate the distribution of the splitting of the magnetic Tb$^{3+}$ non-Kramers ground state doublets and to compare it with excitations measured in inelastic neutron scattering. Combining macroscopic and neutron scattering measurements, we show that a clear spin glass transition at 1 K stems out while retaining strong spin liquid correlations. Our results suggest that Tb$_{2}$ScNbO$_{7}$ stabilizes one of the novel disorder induced quantum spin liquid or topological glassy phases recently proposed theoretically.