Widely Spaced Planes of Magnetic Dimers in the Ba6Y2Rh2Ti2O17-{\delta} Hexagonal Perovskite

TL;DR

This study reports the synthesis and initial characterization of a new hexagonal perovskite material, Ba6Y2Rh2Ti2O17-{ extdelta}, revealing magnetic and thermal properties suggestive of a potential spin liquid ground state.

Contribution

The paper introduces a previously unreported hexagonal perovskite with unique magnetic and thermal properties, highlighting its potential as a spin liquid candidate.

Findings

Presence of widely spaced Rh2O9 dimers in the structure

Observation of a large linear term in specific heat despite insulating behavior

Evidence of magnetic fluctuations consistent with a spin liquid state

Abstract

We report the synthesis and initial characterization of Ba6Y2Rh2Ti2O17-{\delta}, a previously unreported material with a hexagonal symmetry structure. Face-sharing RhO6 octahedra form triangular planes of Rh2O9 dimers that are widely separated in the perpendicular direction. The material displays a small effective magnetic moment, due to the Rh ions present, and a negative Curie-Weiss temperature. The charge transport and optical band gaps are very similar, near 0.16 eV. A large upturn in the heat capacity at temperatures below 1 K, suppressed by applied magnetic fields larger than {{\mu}0H = 2 Tesla, is observed. A large T-linear term in the specific heat ({\gamma}=166 mJ/mol f.u-K2) is seen, although the material is insulating at low temperatures. These results suggest the possibility of a spin liquid ground state in this material.