Unconventional magnetism in the 4d${}^4$ based ($S=1$) honeycomb system Ag${}_3$LiRu${}_2$O${}_6$

Abstract

We have investigated the thermodynamic and local magnetic properties of the Mott insulating system Ag${}_3$LiRu${}_2$O${}_6$ containing Ru${}^{4+}$ (4$d$${}^4$) for novel magnetism. The material crystallizes in a monoclinic $C2/m$ structure with RuO${}_6$ octahedra forming an edge-shared two-dimensional honeycomb lattice with limited stacking order along the $c$-direction. The large negative Curie-Weiss temperature (${\theta }_{CW}$ = -57 K) suggests antiferromagnetic interactions among Ru${}^{4+}$ ions though magnetic susceptibility and heat capacity show no indication of magnetic long-range order down to 1.8 K and 0.4 K, respectively. ${}^7$Li nuclear magnetic resonance (NMR) shift follows the bulk susceptibility between 120-300 K and levels off below 120 K. Together with a power-law behavior in the temperature dependent spin-lattice relaxation rate between 0.2 and 2 K, it suggest dynamic spin correlations with gapless excitations. Electronic structure calculations suggest an $S=1$ description of the Ru-moments and the possible importance of further neighbour interactions as also bi-quadratic and ring-exchange terms in determining the magnetic properties. Analysis of our $\mu$SR data indicates spin freezing below 5 K but the spins remain on the borderline between static and dynamic magnetism even at 20 mK.

10 pages, 11 figures. accepted in Phys. Rev. B

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Cited by in corpus (11)

• Spin-orbit-entangled electronic phases in 4$d$ and 5$d$ transition-metal compounds
• Nonmagnetic $J=0$ State and Spin-Orbit Excitations in K${}_2$RuCl${}_6$
• Highly frustrated magnetism in relativistic ${\mathbf{d}}^4$ Mott insulators: Bosonic analog of Kitaev honeycomb model
• Structural, thermodynamic, and local probe investigations of a honeycomb material Ag${}_3$LiMn${}_2$O${}_6$
• Spin-orbit effects in pentavalent Iridates: Models and materials
• Unusual spin dynamics in the low-temperature magnetically ordered state of Ag${}_3$LiIr${}_2$O${}_6$
• Competing spin-orbital singlet states in the 4$d^4$ honeycomb ruthenate Ag${}_3$LiRu${}_2$O${}_6$
• Gapless to gapless phase transitions in quantum spin chains
• Fluctuation-induced first order phase transitions in Kitaev-like $d^4$ honeycomb magnet
• (H,Li)${}_6$Ru${}_2$O${}_6$ : a possible zero-field Ru${}^{3+}$-based Kitaev Quantum Spin Liquid
• Geometrical frustration and incommensurate magnetic order in Na${}_3$RuO${}_4$ with two triangular motifs