Novel ground state in a rare-earth-based triangular lattice antiferromagnet

The subtle interplay between emergent degrees of freedom in rare-earth-based geometrically frustrated magnets represents a promising platform for the search for enigmatic quantum spin liquids (QSL). QSL state is characterized by the absence of magnetic ordering or freezing down to absolute zero, strong quantum entanglement, and exotic magnetic excitations. Our recent study on a novel class of structurally perfect rare-earth-based triangular lattice family revealed NdTa7O19 as a promising candidate for a QSL stabilized by the strong Ising anisotropy. Here, we focus on a novel triangular lattice antiferromagnet DyTa7O19 from this family. Our preliminary magnetization data do not show any signature of spin-freezing or magnetic ordering down to 1.9 K, while the specific heat shows an anomaly at ~1.5 K and another broad anomaly at 120 mK possibly related to phase transition. However, the entropy release at these temperatures is too low for conventional magnetic ordering. This calls for more sensitive local-probe magnetic investigations that could unambiguously determine the nature of the magnetic ground state and characterize the corresponding magnetic excitations at very low temperatures. Given the localized nature of 4f orbitals, the exchange interactions of this frustrated magnet are, as typically, in the sub-Kelvin range. Therefore, it is imperative to carry out the μSR experiment in the millikelvin range to establish the ground state and associate excitations unambiguously.