Field-tunable partial antiferromagnetism, glassy spin dynamics, and magnetodielectric coupling in the quasi-one-dimensional spin-chain compound Ca3CoIrO6

TL;DR

This study explores the complex magnetic and dielectric behaviors of Ca3CoIrO6, revealing field-tunable partial antiferromagnetism, glassy spin dynamics, and magnetodielectric effects driven by geometric frustration and spin-lattice interactions.

Contribution

It provides a comprehensive experimental analysis demonstrating how geometric frustration and spin-orbit coupling induce novel magnetic and dielectric phenomena in a quasi-one-dimensional spin-chain compound.

Findings

Partial antiferromagnetic order below 100 K

Glassy spin dynamics with freezing near 30 K

Magnetodielectric coupling linked to spin-lattice interactions

Abstract

We report a comprehensive investigation of the quasi-one-dimensional spin-chain compound Ca3CoIrO6 (CCIO) using a combination of structural, magnetic, thermodynamic, transport, Raman, and dielectric measurements. Temperature-dependent neutron powder diffraction confirms the rhombohedral R-3c structure down to 5 K without any structural phase transition. DC magnetization, ac susceptibility, and relaxation measurements reveal a gradual evolution from a high-temperature paramagnetic-like state to a partially disordered antiferromagnetic (PDA) state below 100 K, accompanied by slow cluster-like spin dynamics followed by a freezing transition near 30 K. Isothermal magnetic hysteresis M(H) loops demonstrate partial chain freezing, while robust exchange bias is observed in field-cooled protocols, highlighting the interplay between PDA ordering and frozen spins. Resistivity and specific heat data indicate strong coupling between spin and charge degrees of freedom, accompanied by activated transport behavior. Raman spectroscopy identifies pronounced anomalies in phonon frequencies and linewidths across multiple magnetic regimes, reflecting strong spin-lattice coupling. Polarization-electric field (P-E) measurements reveal temperature-dependent crossovers from linear dielectric to weakly hysteretic behavior, consistent with short-range polar correlations driven by spin-lattice interactions. These findings establish CCIO as a prototypical quasi-one-dimensional frustrated spin-chain system where geometric frustration, spin-orbit coupling, and low-dimensionality generate field-tunable PDA order, glassy spin dynamics, exchange bias, and magnetodielectric coupling. These results provide new insights into frustration-driven phases in low-dimensional oxides and point towards potential multifunctional applications based on intrinsic magnetodielectric and exchange bias phenomena.