Vickers Microhardness Studies for SmBa₂Cu₃O_7-δ Added with NiO Nanosized Particles

The effect of nanosized particles NiO addition on the Vickers microhardness of polycrystalline SmBa₂Cu₃O_7-δ was investigated. Various amounts of nanosized particles NiO (x = 0.00, 0.02, 0.04, 0.08, and 0.12 wt%) were added to SmBa₂Cu₃O_7-δ prepared by the solid-state reaction method. Sample characterizations were carried out using X-ray powder diffraction (XRD), particle induced X-ray emission (PIXE), Rutherford backscattering (RBS), and scanning electron microscopy (SEM). The nanosized particle addition does not influence the orthorhombic structure of SmBa₂Cu₃O_7-δ, whereas it affects the oxygen content δ. The electrical and mechanical properties of (NiO)_xSmBa₂Cu₃O_7-δ samples were measured using four-standard probe technique and Vickers microhardness in order to investigate the effect of NiO nanosized particles on superconducting transition temperature and Vickers microhardness number H_v. The Vickers microhardness data were analyzed using Hays and Kendall (HK), elastic plastic deformation (EPD), and modified proportional specimen resistance (MPSR) models. The analysis showed that the MPSR model was found to be the best to describe the behavior of H_v.