A rock-salt-type Li-based oxide, Li3Ni2RuO6, exhibiting a chaotic ferrimagnetism with cluster spin-glass dynamics and thermally frozen charge carriers.

Sanjay Kumar Upadhyay,Kartik K Iyer,E V Sampathkumaran,S Rayaprol,P L Paulose

doi:10.1038/srep31883

Sanjay Kumar Upadhyay, Kartik K Iyer + Show 3 more

Open Access

https://doi.org/10.1038/srep31883

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Abstract

The area of research to discover new Li containing materials and to understand their physical properties has been of constant interest due to applications potential for rechargeable batteries. Here, we present the results of magnetic investigations on a Li compound, Li3Ni2RuO6, which was believed to be a ferrimagnet below 80 K. While our neutron diffraction (ND) and isothermal magnetization (M) data support ferrimagnetism, more detailed magnetic studies establish that this ferrimagnetic phase exhibits some features similar to spin-glasses. In addition, we find another broad magnetic anomaly around 40–55 K in magnetic susceptibility (χ), attributable to cluster spin-glass phenomenon. Gradual dominance of cluster spin-glass dynamics with a decrease of temperature (T) and the apparent spread in freezing temperature suggest that the ferrimagnetism of this compound is a chaotic one. The absence of a unique freezing temperature for a crystalline material is interesting. In addition, pyroelectric current (Ipyro) data reveals a feature in the range 40–50 K, attributable to thermally stimulated depolarization current. We hope this finding motivates future work to explore whether there is any intriguing correlation of such a feature with cluster spin-glass dynamics. We attribute these magnetic and electric dipole anomalies to the crystallographic disorder, intrinsic to this compound.

Highlights

The phenomenon of spin-glass ordering in which the magnetic moments are randomly frozen as the temperature is lowered below a characteristic temperature (Tg) discovered several decades ago for magnetic impurities in non-magnetic matrices, is commonly observed in many concentrated magnetic systems as well[1,2]
Inverse χexhibits a linear region in a narrow temperature interval (225–300 K), below which there is a deviation from this high-temperature Curie-Weiss behavior, attributable to short-range magnetic correlations; the value of the effective moment obtained from the linear region is about 5.3 μBper formula unit which is very close to that expected (5.57 μB) for high-spin divalent Ni (S = 1) and pentavalent Ru (S = 3/2)
These findings are in agreement with those reported by Laha et al.[11] by measurements with 1 kOe

Summary

Introduction

The phenomenon of spin-glass ordering in which the magnetic moments are randomly frozen as the temperature is lowered below a characteristic temperature (Tg) discovered several decades ago for magnetic impurities in non-magnetic matrices, is commonly observed in many concentrated magnetic systems as well[1,2]. Such a type of magnetic ordering in compounds is usually facilitated by crystallographic order and can be triggered by geometrical frustration [see, for instance, refs 3–5]. A view of the crystal structure of this compound, ignoring disorder, along a-axis is shown in Supplementary Information (see Supplementary Fig. S1)

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