Structural and magnetic properties of two branches of the Tripod Kagome Lattice family A$_{2}$RE$_{3}$Sb$_{3}$O$_{14}$ (A = Mg, Zn; RE = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb)

TL;DR

This study systematically investigates the structural and magnetic properties of the Tripod Kagome Lattice family A$_{2}$RE$_{3}$Sb$_{3}$O$_{14}$, revealing diverse magnetic ground states and the effects of chemical substitution on these states.

Contribution

It provides new insights into how chemical pressure and disorder influence magnetic ground states in the Tripod Kagome Lattice family, expanding understanding beyond previous work.

Findings

Identification of various magnetic ground states including LRO, spin glass, and non-magnetic singlet states.

Observation of the influence of chemical substitution on magnetic interactions and disorder.

Comparison of ground states with those in parent pyrochlore systems.

Abstract

We present a systematic study of the structural and magnetic properties of two branches of the rare earth Tripod Kagome Lattice (TKL) family A$_{2}$RE$_{3}$Sb$_{3}$O$_{14}$ (A = Mg, Zn; RE = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb; here, we use abbreviation \textit{A-RE}, as in \textit{MgPr} for Mg$_{2}$Pr$_{3}$Sb$_{3}$O$_{14}$), which complements our previously reported work on \textit{MgDy}, \textit{MgGd}, and \textit{MgEr} \cite{TKL}. The present susceptibility ($\chi_{dc}$, $\chi_{ac}$) and specific heat measurements reveal various magnetic ground states, including the non-magnetic singlet state for \textit{MgPr}, \textit{ZnPr}; long range orderings (LROs) for \textit{MgGd}, \textit{ZnGd}, \textit{MgNd}, \textit{ZnNd}, and \textit{MgYb}; a long range magnetic charge ordered state for \textit{MgDy}, \textit{ZnDy}, and potentially for \textit{MgHo}; possible spin glass states for \textit{ZnEr}, \textit{ZnHo}; the absence of spin ordering down to 80 mK for \textit{MgEr}, \textit{MgTb}, \textit{ZnTb}, and \textit{ZnYb} compounds. The ground states observed here bear both similarities as well as striking differences from the states found in the parent pyrochlore systems. In particular, while the TKLs display a greater tendency towards LRO, the lack of LRO in \textit{MgHo}, \textit{MgTb} and \textit{ZnTb} can be viewed from the standpoint of a balance among spin-spin interactions, anisotropies and non-Kramers nature of single ion state. While substituting Zn for Mg changes the chemical pressure, and subtly modifies the interaction energies for compounds with larger RE ions, this substitution introduces structural disorder and modifies the ground states for compounds with smaller RE ions (Ho, Er, Yb).