Evidence of Ferromagnetic Short-Range Correlations in Sol–gel Synthesized La1.88 Sr0.12CoMnO6 Nanoparticles

Study of double perovskite compounds of A2BB'O6 type is significant due to the varied properties they exhibit with compositional variation. Structural and magnetic properties of La2CoMnO6 (LCMO) doped with Sr at La site in smaller concentration (La1.88 Sr0.12CoMnO6) are studied in this paper. LCMO and LSCMO (La1.88 Sr0.12CoMnO6) nanoparticles are synthesized by sol–gel method. To investigate its structural properties XRD, FTIR, and Raman techniques have been used. The detailed Rietveld refinement of XRD data shows the formation of rhombohedral type structure (S.G. No. R3c: 161) for the prepared nanoparticles. Estimated crystallite size from Debye Scherrer formula is found to be in the range of ~6–18 nm. The vibration bands obtained by FTIR and Raman study also confirms the formation of Sr doped LCMO nanoparticle. Magnetization (M–H) curve at room temperature shows the paramagnetic behavior of the prepared nanoparticles. M-H curves recorded at 250, 200, 150, and 60 K indicate the paramagnetic to ferromagnetic transition below 200 K. Temperature-dependent magnetization study indicates super-exchange interactions of Co2+–O2−–Mn4+ and Co3+–O2−–Mn4+ in the parent compound. Due to Sr doping in LCMO host lattice the antisite disorder is enhanced and the temperature dependent magnetization study indicates the existence of ferromagnetic short-range correlations similar to the Griffiths like phase.