Insight into the magnetism of a distorted Kagome lattice, Dy3Ru4Al12, based on polycrystalline studies

TL;DR

This study investigates the complex magnetic behavior of polycrystalline Dy3Ru4Al12 with distorted Kagome nets, revealing additional magnetic anomalies, potential spin-glass-like dynamics, and complex magnetoresistance features, indicating more intricate magnetism than previously understood.

Contribution

It provides new insights into the magnetic properties of polycrystalline Dy3Ru4Al12, highlighting the role of geometric frustration and revealing phenomena not observed in single crystals.

Findings

Additional magnetic anomaly around 20 K indicating ferromagnetic clusters

Frequency dependence of ac susceptibility near TN suggesting spin-glass-like dynamics

Butterfly-shaped magnetoresistance loop indicating magnetic phase coexistence

Abstract

The layered compound with distorted Kagome nets, Dy3Ru4Al12, was previously reported to undergo antiferromagnetic ordering below (TN=) 7 K, based on investigations on single crystals. Here, we report the results of our investigation of ac and dc magnetic susceptibility (\c{hi}), isothermal remnant magnetization (MIRM), heat-capacity, magnetocaloric effect and magnetoresistance measurements on polycrystals. The present results reveal that there is an additional magnetic anomaly around 20 K, as though the N\'eel order is preceded by the formation of ferromagnetic clusters. We attribute this feature to geometric frustration of magnetism. In view of the existence of this phase, the interpretation of the linear-term in the heat-capacity in terms of spin-fluctuations from the Ru 4d band needs to be revisited. Additionally, in the vicinity of TN, AC \c{hi} shows a prominent frequency dependence and, below TN, MIRM exhibits a slow decay with time. This raises a question whether the antiferromagnetic structure in this compound is characterized by spin-glass-like dynamics. In contrast to what was reported earlier, there is a change in the sign of the magnetoresistance (MR) at the metamagnetic transition. A butter-fly-shaped (isothermal) MR loop (interestingly spanning over all the four quadrants) is observed at 2 K with distinct evidence for the magnetic phase co-existence phenomenon in zero field after travelling through metamagnetic transition field. The results on polycrystals thus provide additional information about the magnetism of this compound, revealing that the magnetism of this compound is more complex than what is believed, due to geometric frustration intrinsic to Kagome net.