Experimental_FTIR_Characterisation_WP2_TSNUK

This dataset was generated as part of APPROACH project activities (specifically Task 2.5 of WP2), to support the characterization of advanced materials for energy storage, energy harvesting and nanogenerators. To the best of our knowledge, the influence of the preparation conditions and size effects on the structural and multiferroic properties of LuFeO3 nanoparticles (LFO NPs) are very poorly studied. To fill the gap in the knowledge, we use the combination of the Raman and Fourier-transform infrared (FTIR) spectroscopies, and theoretical approaches to establish the influence of sintering temperature and size effects on the properties of the LFO NPs. We revealed a gradual substitution of the hexagonal phase by the orthorhombic phase in the nanoparticles, with sintering temperature increasing from 700 to 1100 °С. The origin and stability of the hexagonal phase in the LuFeO3 nanoparticles are of the special interest, because the nanoparticles in the phase can be a room-temperature multiferroic with a weak ferromagnetic and pronounced structural and ferroelectric long-range ordering. The antiferromagnetic and nonpolar orthorhombic phase is more stable in the bulk LuFeO3. To define the ranges of the hexagonal phase stability, we determine the bulk and interface energy densities of different phases from the comparison of the Gibbs model with experimental results. Using effective parameters of the Gibbs model, we predict the influence of size effects and temperature on the structural and polar properties of the LuFeO3 nanoparticles. Analysis of the obtained results shows that the combination of the x-ray diffraction, Raman and infrared spectroscopies, magnetic measurements, and theoretical modeling of structural and polar properties allows us to establish the interplay between the phase composition, lattice dynamics, and multiferroic properties of the LuFeO3 nanoparticles prepared under different conditions.