Coexistence of static and dynamic local magnetic fields in an S = 3/2 honeycomb lattice antiferromagnet Co2Te3O8

TL;DR

This study investigates the magnetic properties of Co2Te3O8, revealing coexistence of static and dynamic magnetic fields below 55 K, with evidence of complex XY-like antiferromagnetic order in a S=3/2 honeycomb lattice.

Contribution

It provides the first comprehensive experimental and theoretical analysis of Co2Te3O8, highlighting its long-range antiferromagnetic order and coexistence of static and dynamic magnetic fields in a S=3/2 honeycomb system.

Findings

Long-range antiferromagnetic order below 55 K.

Coexistence of static and dynamic magnetic fields.

XY-like antiferromagnetic structure confirmed.

Abstract

Two-dimensional honeycomb lattices, characterized by their low coordination numbers, provide a fertile platform for exploring various quantum phenomena due to the intricate interplay between competing magnetic interactions, spin-orbit coupling, and crystal electric fields. Beyond the widely studied Jeff= 1/2 honeycomb systems, S = 3/2 honeycomb lattices present a promising alternative route to realizing the classical spin liquid-like state within the spin-S Kitaev models. Herein, we present crystal structure, thermodynamic, neutron diffraction and muon spin relaxation (muSR) measurements, complemented by density functional theory (DFT) calculations on an unexplored 3d transition metal based compound Co2Te3O8, where Co2+ (S = 3/2) ions form a distorted honeycomb lattice in the crystallographic bc-plane without any anti-side disorder between constituent atoms. A clear lambda type anomaly around 55 K in both magnetic susceptibility and specific heat data indicates the onset of a long-range ordered state below TN= 55 K. The dominant antiferromagnetic interaction between S = 3/2 moments is evidenced by a relatively large negative Curie-Weiss temperature of -103 K derived from magnetic susceptibility data and supported by DFT calculations. The signature of long-range antiferomagnetic order state in the thermodynamic data is corroborated by neutron diffraction and muSR results. Furthermore, muSR experiments reveal the coexistence of static and dynamic local magnetic fields below TN, along with a complex magnetic structure that can be associated with XY-like antiferromagnet, as confirmed by neutron diffraction experiments.