Magnetic anomalies in nanocrystalline Ca3CoRhO6, a geometrically frustrated spin-chain compound,

TL;DR

This study explores how nanocrystalline Ca3CoRhO6 differs magnetically from its bulk form, revealing changes in magnetic ordering and dynamics due to nanoscale effects, which enhances understanding of geometrical frustration in spin-chain systems.

Contribution

It provides new insights into the magnetic behavior of nanocrystalline Ca3CoRhO6, highlighting differences from bulk material and the preservation of certain spin dynamics at the nanoscale.

Findings

Partially disordered antiferromagnetism is absent in nanoparticles.

Magnetic moment at low temperatures is enhanced in nanoparticles.

Spin dynamics with frequency dependence are retained in nanoparticles.

Abstract

We have investigated the magnetic behavior of the nano crystals, synthesized by high-energy ball-milling, for a well-known geometrically frustrated spin-chain system, Ca3CoRhO6, and compared its magnetic characteristics with those of the bulk form by measuring ac and dc magnetization. The features attributable to the onset of 'partially disordered antiferromagnetism' (characterizing the bulk form) are not seen in the magnetization data of the nano particles; the magnetic moment at high fields in the very low temperature range in the magnetically ordered state gets relatively enhanced in the nano particles. It appears that the ferromagnetic intrachain interaction, judged by the sign of the paramagnetic Curie temperature, is preserved in the nano particles. These trends are opposite to those seen in Ca3Co2O6. However, the complex spin-dynamics as evidenced by large frequency dependence of ac susceptibility is retained in the nano particles as well. Thus, there are some similarities and dissimilarities between the properties of the nano particles and those of the bulk. We believe that these findings would be useful to understand correlation lengths deciding various properties of geometrical frustration and/or spin-chain phenomena.