Magnetic frustration in the stoichiometric spin-chain compound Ca₃CoIrO₆

Abstract

The temperature dependent ac and dc magnetization and heat capacity data of Ca₃CoIrO₆, a spin-chain compound crystallizing in a K₄CdCl₆-derived rhombohedral structure, show the features due to magnetic ordering of a frustrated type below about 30 K, however without exhibiting the signatures of the so-called "partially disordered antiferromagnetic structure" encountered in the isostructural compounds, Ca₃Co₂O₆ and Ca₃CoRhO₆. This class of compounds thus provides a variety for probing the consequences of magnetic frustration due to topological reasons in stoichiometric spin-chain materials, presumably arising from subtle differences in the interchain and intrachain magnetic coupling strengths. This compound presents additional interesting situations in the sense that, ac susceptibility exhibits a large frequency dependence in the vicinity of 30 K uncharacteristic of conventional spin glasses, with this frustrated magnetic state being robust to the application of external magnetic fields.