# Absence of magnetic long range order in Ba$_3$ZnRu$_2$O$_9$: A spin-liquid candidate in the $S=3/2$ dimer lattice

## TL;DR

This study identifies Ba$_3$ZnRu$_2$O$_9$ as a potential spin liquid candidate with no magnetic order down to extremely low temperatures, highlighting the role of dimer spin states in quantum magnetism.

## Contribution

It reports the discovery of a spin liquid state in a $S=3/2$ dimer ruthenium oxide, revealing the influence of dimer spin states and substitution on magnetic ground states.

## Key findings

- No long-range magnetic order down to 37 mK.
- Partial substitution tunes the ground state from antiferromagnetic to spin-gapped.
- Spin-liquid state arises from a balance of inter- and intra-dimer interactions.

## Abstract

We have discovered a novel candidate for a spin liquid state in a ruthenium oxide composed of dimers of $S = $ 3/2 spins of Ru$^{5+}$,Ba$_3$ZnRu$_2$O$_9$. This compound lacks a long range order down to 37 mK, which is a temperature 5000-times lower than the magnetic interaction scale of around 200 K. Partial substitution for Zn can continuously vary the magnetic ground state from an antiferromagnetic order to a spin-gapped state through the liquid state. This indicates that the spin-liquid state emerges from a delicate balance of inter- and intra-dimer interactions, and the spin state of the dimer plays a vital role. This unique feature should realize a new type of quantum magnetism.