Removing the spin ice cap: magnetic ground states of rare earth tripod kagome lattice Mg$_2$RE$_3$Sb$_3$O$_{14}$ (RE = Gd, Dy, Er)

TL;DR

This study investigates the magnetic ground states of a new family of tripod kagome lattice compounds Mg$_2$RE$_3$Sb$_3$O$_{14}$ (RE = Gd, Dy, Er), revealing diverse magnetic behaviors including long-range order and quantum fluctuations.

Contribution

It introduces a new tripod kagome lattice compound family and characterizes their magnetic properties, highlighting the influence of different rare earth elements on magnetic ground states.

Findings

Gd compound exhibits long-range order at 1.65 K with a 120° structure.

Dy compound shows order at 0.37 K related to kagome spin ice physics.

Er compound displays two transitions at 80 mK and 2.1 K, indicating quantum fluctuations.

Abstract

We present the structural and magnetic properties of a new compound family, Mg$_2$RE$_3$Sb$_3$O$_{14}$ (RE = Gd, Dy, Er), with a hitherto unstudied frustrating lattice, the "tripod kagome" structure. Susceptibility (ac, dc) and specific heat exhibit features that are understood within a simple Luttinger-Tisza type theory. For RE = Gd, we found long ranged order (LRO) at 1.65 K, which is consistent with a 120 $^{\circ}$ structure, demonstrating the importance of diople interactions for this 2D Heisenberg system. For RE = Dy, LRO at 0.37 K is related to the "kagome spin ice (KSI)" physics for a 2D system. This result shows that the tripod kagome structure accelerates the transition to LRO predicted for the related pyrochlore systems. For RE = Er, two transitions, at 80 mK and 2.1 K are observed, suggesting the importance of quantum fluctuations for this putative XY system.