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In the present work, the phase conversion of amorphous calcium phosphate (ACP) in different molten chlorides (LiCl, NaCl, KCl, CaCl 2) was investigated in detail. The main synthesis parameters influencing the phase purity and morphological features of the products include the chemical composition of molten salts, the heat treatment temperature and the ACP-to-flux ratio. The selective synthesis of single-phase Ca 5 (PO 4) 3 Cl or Ca 2 PO 4 Cl depends on the content of CaCl 2 in the reaction medium. The morphology control of Ca 5 (PO 4) 3 Cl powders was achieved by varying the KCl/CaCl 2 ratio in the flux, resulting in the formation of the particles of different size and shape. The KCl-rich fluxes led to the formation of relatively small nearly spherical particles, whereas the CaCl 2 -rich fluxes promoted an anisotropic growth of the Ca 5 (PO 4) 3 Cl crystals resulting in the formation of monodispersed hexagonally-shaped microrods. Whereas the anisotropic growth was observed at relatively low temperature (750 °C) the increase of the reaction temperature up to 1200 °C significantly reduced this effect leading to the formation of the particles with obviously low aspect ratio. The phase crystallinity and purity were analyzed using powder X-ray diffraction, FTIR spectroscopy as well as 31P, 35Cl and 1H solid-state NMR. The morphological features and chemical composition of the synthesized products were studied by SEM/EDX analysis. [ABSTRACT FROM AUTHOR]

In this study, solid solutions of (1-x)BaTiO 3 -xBiMnO 3 have been synthesized by an aqueous sol-gel method. It was determined that single-phase compounds can be obtained up to x = 0.6 and with further increase in percentage of BiMnO 3 component additional crystal phases were detected. Perovskite crystal structure was determined for all synthesized compounds regardless of chemical composition. Raman spectra of synthesized solid solutions showed gradual change of the shape with an increase of BiMnO 3 fraction. It was demonstrated that partial substitution of BaTiO 3 by BiMnO 3 led to the drastic growth of grains of the end products. Magnetization measurements showed that all BiMnO 3 -containing samples are characterized by paramagnetic behavior. Clear correlation between magnetization values and composition of the materials was observed, magnetization values increased with increasing of BiMnO 3 content in solid solutions. [ABSTRACT FROM AUTHOR]

In the present work, a series of powdered Y 1-x Gd x FeO 3 solid solutions (x from 0 to 1) was prepared by an aqueous sol-gel method. Structural properties of the synthesized species were investigated using powder X-ray diffraction (XRD), Raman and Mössbauer spectroscopies. It was demonstrated that single-phase compounds can be obtained in the whole compositional range between the end members of the series. Raman study revealed a gradual change of the Raman spectra depending on the chemical composition of samples. Room-temperature magnetic properties were shown to be strongly dependent on the ratio of Y3+ and Gd3+ ions in analyzed species. Consistent transition from hysteresis characteristic of YFeO 3 to almost linear dependence of magnetization of GdFeO 3 was observed with an increase of Gd content in prepared powders. On the other hand, this transition was accompanied by a significant increase of magnetization values. [Display omitted] • Y 1-x Gd x FeO 3 powders were prepared by an aqueous sol-gel method. • Solid solutions were obtained in the whole compositional range between the end members. • Magnetic properties gradually changed along with chemical composition. [ABSTRACT FROM AUTHOR]

In this study, BiFe 1-x Mn x O 3 (BiFeMnO; x from 0 to 0.5) solid solutions were prepared by low temperature sol-gel processing. It was demonstrated that structural, magnetic and morphological properties of BiFeMnO samples are dependent on the chemical composition of the synthesized BiFe 1-x Mn x O 3 solid solutions. The thermal behaviour of the Bi–Fe–Mn–O precursor gels was investigated by thermogravimetric and differential scanning calorimetry (TG-DSC) measurements. From X-ray diffraction (XRD) analysis it was observed that monophasic BiFe 1-x Mn x O 3 samples have formed up to 25 mol% of substitution. The Rietveld analysis showed that the structure of BiFeMnO specimens can be indexed by rhombohedral or orthorhombic unit cell depending on Mn3+ content. Scanning electron microscopy (SEM) was used to investigate samples morphology and revealed, that smaller particles form when Mn3+ is present inside the structure. Moreover, magnetic properties of solid solutions were also investigated, and antiferromagnetism and weak ferromagnetism were observed for the samples. Image 1 • BiFe 1-x Mn x O 3 solid solutions were prepared by low temperature sol-gel processing. • The monophasic BiFe 1-x Mn x O 3 samples have formed up to 25 mol% of substitution of manganese. • The rhombohedral or orthorhombic structure of specimens depends on Mn content. • Smaller particles formed when Mn3+ was present in the structure. • Weak ferromagnetism was observed for the samples containing Mn3+. [ABSTRACT FROM AUTHOR]