Structural, transport and optical properties of (La0.6Pr0.4)0.65Ca0.35MnO3 nanocrystals: a wide band-gap magnetic semiconductor

Abstract

(La_0.6Pr_0.4)_0.65Ca_0.35MnO₃ system has been synthesized via a sol–gel route at different sintering temperatures. Structural, transport and optical measurements have been carried out to investigate (La_0.6Pr_0.4)_0.65Ca_0.35MnO₃ nanoparticles. Raman spectra show that Jahn–Teller distortion has been decreased due to the presence of Ca and Pr in A-site. Magnetic measurements provide a Curie temperature around 200 K and saturation magnetization (M_S) of about 3.43μ_B/Mn at 5 K. X-ray photoemission spectroscopy study suggests that Mn exists in a dual oxidation state (Mn³⁺ and Mn⁴⁺). Resistivity measurements suggest that charge-ordered states of Mn³⁺ and Mn⁴⁺, which might be influenced by the presence of Pr, have enhanced insulating behavior in (La_0.6Pr_0.4)_0.65Ca_0.35MnO₃. Band gap estimated from UV-Vis spectroscopy measurements comes in the range of wide band gap semiconductors (∼3.5 eV); this makes (La_0.6Pr_0.4)_0.65Ca_0.35MnO₃ a potential candidate for device application.