Synthesis, structure, optical and magnetic properties of Nd1-xAxMn0.5Co0.5O3-δ (A = Ba, Sr and Ca; x=0 and 0.25)

The structural, optical, and magnetic properties of polycrystalline Nd(1-x)A(x)Mn(0.5)Co(0.5)O(3-delta) (A = Ba, Sr and Ca; x = 0 and 0.25) perovskite oxides were investigated. The powder XRD pattern demonstrates that the unit cell volume decreases with the changing A-site dopant type. The estimated bandgap energy (Eg) from UV-vis spectroscopic for NdMn0.5Co0.5O3-delta, Nd0.75Ba0.25Mn0.5Co0.5O3-delta, Nd0.75Sr0.25Mn0.5Co0.5O3-delta and Nd0.75Ca0.25Mn0.5Co0.5O3-delta are 3.27, 3.82, 3.79 and 3.53 eV respectively. The substitution of divalent element alters the absorption spectrum, while the redshift optical transition was observed with an increasing ionic radius of dopant. Temperature-dependent magnetization exposes that the Curie temperature (TC) gradually decreases with the decreasing size of alkaline earth metals, and glassy nature was observed at a lower applied magnetic field. The observation of TC can be well explained by the considering of the cationic size disorder parameter in A-site than the random distribution of B-site ions.