Comprehensive Investigation of Structural, Electrical, and Magnetic Properties of Dy2CoIrO6: A 3d–5d–4f Heterotri-Spin System

Abstract In this work, we present a comprehensive investigation of the structural, electrical, and magnetic properties of Dy2CoIrO6, a 3d–5d–4f heterotri-spin system. X-ray diffraction analysis confirms a distorted monoclinic crystal structure (space group: P21/n) with slight antisite disorder (∼8%) between the Co and Ir ions. X-ray photoelectron spectroscopy reveals the coexistence of mixed valence of Co2+/3+ and Ir4+/5+ ions. The high electrical resistivity confirms the insulating nature of the compound, while the low-temperature transport behavior is well described by the 3D variable-range hopping model. The dc magnetization exhibits two magnetic transition temperatures at TN1 = 21.5 K and TN2 = 145 K, together with a magnetic compensation temperature of approximately 61 K. The magnetic transition below TN1 is attributed to weak ferrimagnetic ordering arising from antiferromagnetic coupling between the Dy(4f) and Co(3d)/Ir(5d) sublattices, whereas the transition at TN2 is associated with antiferromagnetic ordering resulting from antiferromagnetic interactions between the Co and Ir spins. A detailed analysis of the ac susceptibility exhibits a pronounced frequency dependence of the spin-freezing temperature, indicating the presence of glassy magnetic behavior below 11.5 K in Dy2CoIrO6 compound.