Structural Study of [Nd0.5 (Ca0.25Ba0.25) MnO3] and [Nd0.5(Ca0.25Sr0.25)MnO3] Perovskites at Room Temperature

Two perovskite manganite compounds, namely, Nd0.5(Ca0.25Ba0.25)MnO3
and Nd0.5(Ca0.25Sr0.25)MnO3 have been studied by X-ray diffraction (XRD) at
room temperature. The perovskite manganite Nd0.5(Ca0.25Ba0.25)MnO3, was
found to be orthorhombic with space group Pbnm and the lattice parameters
are a = 5.4377 Å, b = 5.4387 Å, and c= 7.7084 Å. The second perovskite
Nd0.5(Ca0.25Sr0.25)MnO3 was found to be also orthorhombic with space group < br />Pbnm and the lattice parameters are a = 5.4078 Å, b = 5.4106 Å, and c
= 7.6704 Å. The differences in the lattice parameters and unit cell volumes of
the two systems are likely lead to influence the transport, structure, and
magnetic properties of this type of materials. The difference in the unit cell
volumes for the two samples is attributed to the differences in the ionic radii of
the substituted divalent alkaline earth ions present in the A-site of the two
compounds.