Incommensurately modulated phase and charge ordering transition in nanocrystalline Nd0.5Sr0.5MnO3 perovskite

Abstract

We report here the “incommensurate modulated” phase along with the ferromagnetic character in nanocrystalline Nd0.5Sr0.5MnO3 perovskite. The Rietveld analysis of powder X-ray diffraction data reveals that the structure of nanocrystalline Nd0.5Sr0.5MnO3 ceramic can be described as a modulated phase in the monoclinic structure with space group Pm and lattice parameters am ≈ 2ao, bm ≈ bo, and cm ≈ 3co, where ao, bo, and co correspond to the lattice parameters of the parent orthorhombic structure for the bulk sample at room temperature. Increasing the crystallite size converts the modulated monoclinic structure to an orthorhombic structure with the Imma space group for the bulk Nd0.5Sr0.5MnO3 sample. The magnetic measurements on nanocrystalline samples reveal ferromagnetic behaviour and the absence of charge ordering transition at low temperatures. The nanocrystalline samples also exhibit Griffith phase like behaviour near the paramagnetic to ferromagnetic phase transition. The Powder X-ray diffraction study of bulk Nd0.5Sr0.5MnO3 in the temperature range of 13 K–300 K reveals the transition from the orthorhombic to the monoclinic structure in the P21/m space group with the coexistence of the two phases in a wide temperature range below room temperature.