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A study was undertaken about the structural, morphological and magnetic properties at room temperature of crystalline aluminium substituted yttrium iron garnet, YIG (Y3Fe5-xAlxO12 with 1.5< x < 1.7) nanoparticles prepared by polymeric precursormethod at the temperature of 700?C for 2 hours. The single-phase character and the well-defined structure of YIG nanoparticles were confirmed by X-ray diffraction, excluding the presence of any other phases. The Raman spectra showed that the changes of lattice vibration would influence interaction between the Fe ion and the host. Mean crystallite size of the single-phase powder was about 46-65 nm. Particles? morphology was investigated by high-resolution transmission electron microscopy, which shows that the particles were agglomerated. From hysteresis loops, particles? efficiency range from 91.4% to 95.9% as Fe/Al ratio decreases. Saturation magnetization was affected by the particle size and Fe/Al stoichiometric ratio. We observe that the saturation magnetization increases as the Fe/Al ratio is raised due to enhancement of the surface spin effects.

In this work, we focus on understanding the morphology and photocatalytic properties of CeO2 nanocrystals (NCs) synthesized via a microwave-assisted solvothermal method using acetone and ethanol as solvents. Wulff constructions reveal a complete map of available morphologies and a theoretical-experimental match with octahedral nanoparticles obtained through synthesis using ethanol as solvent. NCs synthesized in acetone show a greater contribution of emission peaks in the blue region (∼450 nm), which may be associated with higher Ce3+ concentration, originating shallow-level defects within the CeO2 lattice while for the samples synthesized in ethanol a strong orange-red emission (∼595 nm) suggests that oxygen vacancies may originate from deep-level defects within the optical bandgap region. The superior photocatalytic response of CeO2 synthesized in acetone compared to that of CeO2 synthesized in ethanol may be associated with an increase in long-/short-range disorder within the CeO2 structure, causing the E gap value to decrease, facilitating light absorption. Furthermore, surface (100) stabilization in samples synthesized in ethanol may be related to low photocatalytic activity. Photocatalytic degradation was facilitated by the generation of ·OH and ·O2 – radicals as corroborated by the trapping experiment. The mechanism of enhanced photocatalytic activity has been proposed suggesting that samples synthesized in acetone tend to have lower e′h· pair recombination, which is reflected in their higher photocatalytic response.

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The origin of abnormal ferroelectric and unusual piezoelectricity in the polycrystalline CaCu 3 Ti 4 O 12 (CCTO) thin films deposited by RF-sputtering on Pt/Ti/SiO 2 /Si (100) substrates was explored. The CCTO thin films, deposited at room temperature followed by annealing at 600°C for 2 h in a conventional furnace, have a cubic structure with lattice parameter a = 7.379 ± 0.001 Å and without any secondary phases. No polarization loss up to 10 10 switching cycles, with a switched polarization ∆P of 30 µC/cm 2 measured at 400 kV/cm was evidenced. The piezoelectric coefficient investigated by piezoresponse force microscopy (PFM) was approximately 9.0 pm/V. This may be the very first example of exploring the origin of ferroelectric behaviour for a material that possesses space charge polarization with highly resistive grain boundaries in the polycrystalline state.

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