Structural and magnetic properties of R0.5Sr0.5Fe0.5Mn0.5O3 (R = Gd, Nd or Pr) perovskites

Highlights: • Previously unreported rare earth doped perovskites. • Variation in size of rare earths. • Structure dependent magnetic properties investigated. • Jahn-Teller distortion and Octahedral tilts influence magnetic properties. -- Abstract: In this report, we investigate the effect of A-site substitution on the structure and magnetic properties of perovskite compounds R_0.5Sr_0.5Fe_0.5Mn_0.5O₃ (R = Gd, Nd, or Pr). On Rietveld refinement of the powder X-ray diffraction data, it was seen that Gd_0.5Sr_0.5Fe_0.5Mn_0.5O₃, Nd_0.5Sr_0.5Fe_0.5Mn_0.5O₃, and Pr_0.5Sr_0.5Fe_0.5Mn_0.5O₃ were satisfactorily refined in the orthorhombic space group, Pbnm. We see that substitution at the A-site with rare earth cations of increasing size from Gd, Nd to Pr, leads to decrease in octahedral distortion. This octahedral distortion arises from octahedral tilts and due to the Jahn-Teller distortion afforded by the Mn³⁺ and Fe⁴⁺ ions. Gd_0.5Sr_0.5Fe_0.5Mn_0.5O₃ exhibits canted antiferromagnetism associated with the Mn³⁺ spins, observed around 49 K followed by a low temperature antiferromagnetic Gd³⁺ spin ordering at ~3 K. For Nd_0.5Sr_0.5Fe_0.5Mn_0.5O₃ and Pr_0.5Sr_0.5Fe_0.5Mn_0.5O₃ samples, a spin glass like nature was observed below 47 K and 58 K respectively. Magnetic nature of all the systems is further characterized by the isothermal field dependent magnetization studies, show the existence of canted antiferromagnetism in Gd_0.5Sr_0.5Fe_0.5Mn_0.5O₃ and glass like behavior in Nd_0.5Sr_0.5Fe_0.5Mn_0.5O₃ and Pr_0.5Sr_0.5Fe_0.5Mn_0.5O₃. The core level X-ray photoelectron spectroscopy (XPS) studies show that a significant amount of the Fe and Mn ions are in + 3 and + 4 oxidation states.