The present study investigates the influence of incorporating a small fraction (0.5–5 wt %) of nanoparticles into bulk particles of identical composition in hole-doped La0.82Sr0.18MnO3. Nano–micron composites were synthesized by systematically varying the nanoparticle content. Powder X-ray diffraction combined with Rietveld refinement confirmed the formation of single-phase materials with a rhombohedral (R3c) structure for all compositions, indicating the absence of secondary phases. Magnetic measurements revealed a non-monotonic variation in saturation magnetization with nanoparticle content, with a maximum enhancement of approximately 30% observed for the composite containing ~ 1 wt% nanoparticles. This enhancement correlates with improved densification and a reduction in specific surface area, as discussed in terms of modified grain connectivity and grain-boundary effects arising from nano–micron interfaces. At higher nanoparticle concentrations, the magnetization decreases which is attributed to increased interfacial disorder and surface spin frustration. The results demonstrate that microstructural tuning through controlled nano–micron composite formation plays a crucial role in governing ferromagnetic behavior in manganite systems and provides insight into interface-driven magnetic responses in heterogeneous perovskite oxides.
Bharat Kumar (Sun,) studied this question.