Impact of Nd and Sr-site deficiencies on the structural, magnetic and electrical transport properties in Nd0.67-xSr0.33MnO3-δ (x = 0.09, 0.17, 0.25, 0.33) and Nd0.67Sr0.33-yMnO3-δ (y = 0.09, 0.17) manganites

The effect of Nd and Sr-deficiencies on the magnetic and electrical transport properties of Nd_0.67-xSr_0.33MnO_3-δ (x = 0.09, 0.17, 0.25, 0.33) and Nd_0.67Sr_0.33-yMnO_3-δ (y = 0.09, 0.17) compounds were investigated. The conventional solid-state method was adopted for the preparation of the compounds. Rietveld refinement was used to analyze the X-ray diffraction patterns of the synthesized compounds. The scanning electron microscopy along with energy dispersive X-ray spectroscopy analysis was used to examine the surface morphology and homogeneity. The effective ionic oxidation states of Mn-ions was calculated from the X-ray absorption spectroscopic technique via the interpolation method. Temperature variation of magnetization under a constant static field of 50 Oe confirmed that all the deficient compounds undergo a ferromagnetic to paramagnetic transition similar to the pristine compound, but T_C increases with the increase in Nd-deficiency and decreases with the increase in Sr-deficiency. Among the studied compounds, Nd_0.67-xSr_0.33MnO_3-δ (x = 0.17) composition shows the highest magnetic transition temperature with the least value of electrical resistivity and significant magnetization than that of the pristine compound. Hence, the present study confirms that the structural, magnetic and electrical transport properties of Nd_0.67-xSr_0.33MnO_3-δ (x = 0.09, 0.17, 0.25, 0.33) and Nd_0.67Sr_0.33-yMnO_3-δ (y = 0.09, 0.17) manganites are significantly influenced by the creation of deficiency at the Nd and Sr-sites.