Short range magnetic correlation, metamagnetism and coincident dielectric anomaly in Na$_5$Co$_{15.5}$Te$_6$O$_{36}$

TL;DR

This study investigates the magnetic, dielectric, and structural properties of Na$_5$Co$_{15.5}$Te$_6$O$_{36}$, revealing short-range magnetic correlations, metamagnetism, and dielectric anomalies linked to spin-lattice coupling and potential low-temperature refrigeration applications.

Contribution

It provides new insights into the interplay of magnetic correlations, dielectric anomalies, and metamagnetism in a Co-based compound, highlighting spin-lattice coupling effects.

Findings

Short-range magnetic correlations above T_N=50 K.

Presence of metamagnetic transition under magnetic field.

Correlation between magnetic, dielectric, and structural anomalies.

Abstract

Here we explore the structural, magnetic and dielectric properties of Co based compound Na$_5$Co$_{15.5}$Te$_6$O$_{36}$ as a candidate of short-range magnetic correlations driven development of dielectric anomaly above N$\acute{e}$el temperature of ($T_N$=) 50 K. Low temperature neutron powder diffraction (NPD) in zero applied magnetic field clearly indicates that the canted spin structure is responsible for the antiferromagnetic transition and partially occupied Co form short range magnetic correlation with other Co, which further facilitates the structural distortion and consequent development of dielectric anomaly above antiferromagnetic transition. Additionally, the temperature dependent magnetic heat capacity and electron spin resonance measurements reveal the presence of short-range magnetic correlations which coincides with an anomaly in the dielectric constant vs temperature curve. Moreover, significant changes in the lattice parameters are also observed around the same temperature, indicating presence of noticeable spin-lattice coupling. Further, sharp jump in the magnetic field dependent magnetization clearly indicates the presence of metamagnetic transition and magnetic field dependent NPD confirms that rotations of Co spins with applied magnetic field are responsible for this metamagnetic phase transition. As a result, this transition causes the magnetocaloric effect to be developed in the system, which is suitable for the application in low temperature refrigeration.