Lithium Ferrite Nanocrystals Embedded in a non-Magnetic Glass Matrix

Nanocrystalline LiFe5O8 particles embedded in an amorphous matrix were obtained by heat treatments of the non-magnetic oxide glass 32Li2O-8FeO3-60B2O3, between 200 and 770°C. The X-ray spectra reveal the formation of the spinel phase of Li-ferrite in the initially amorphous materials only for annealing temperatures higher than 440°C and the hybrid structure becomes more evident with the increase of temperature. The occurrence of the magnetic spinel phase (LiFe5O8) was proved by magnetization and Curie temperature measurements too. The evolution of the magnetic properties of these glass-ceramic compounds in terms of annealing temperature was investigated. The magnetic properties (σs, Hc) are correlated with the average size of the LiFe5O8 nanoparticles dispersed in the glass matrix. The X-ray diffraction data indicated an evident increase in the average crystal block size from 3.5 to 50 nm with the increase of annealing temperature from 440° to 770°C

On the possible pyrochlore to aurivillius phase transition in the complex oxide CaCd2Bi2Nb4O15

The sample CaCd2Bi2Nb4O15 was synthesised by the standard ceramic method, starting from a mixture of oxides heated up to 1250°C. The chemical composition indicate that the oxide could have an Aurivillius or a substituted pyrochlore structure. The X-ray diffraction and IR spectra suggest a phase transition from pyrochlore, at -196°C, to Aurivillius at room temperature. The DSC analyses performed in the temperature range 20-400°C did not evidenced major phase transitions for the material

Synthesis, Structural analysis and Magnetic properties of Sc-doped Nd0.8Sr0.2Mn1-xScxO3 Manganites.

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Magnesium-zinc ferrite with copper substitutions

The effects of Mg substitution by Cu on the properties of MgZn ferrites sintered at low temperature are investigated. The densification of MgCuZn ferrites is dependent upon Cu content in the composition Mg0.5-xCuxZn0.5Fe2O4 + 0,5 MgO. From the sintering experiments carried out between 800 and 1100° C it was established the optimum amount of CuO (x = 0.3) which is sufficient to promote sintering at low temperature (1050°C) and to yield a dense material (4,5 g/cm3). It was evidenced a break in the resistivity for x > 0,3 when it decreases by four orders of magnitude. The strong dependence of the material parameters on the Cu ions content is consistent with the microstructural changes induced by copper ions which favour the lattice diffusion process

Structural Changes in the Perovskitic Compounds Series Sr2Mg1-xMIIxMoO6

Two series of perovskite type compounds (Sr2Mg1-xZnxMoO6 and Sr2Mg1-xNixMoO6) are characterized from the structural point of view. The synthesis conditions are briefly described. The cation distribution of the two series compounds were determined by X-ray diffraction

Monitoring techniques for nanocrystalline stabilized zirconia from some medical prosthesis

International audienceThe paper proposes the investigation of influence of doping with Ce ions to the phase stability and mechanical properties of zirconium dioxide. For this investigation, we used X-ray and neutron diffraction, electron microscopy and microstructure characterization, including Resonant Ultrasound Spectroscopy (RUS) for nondestructive evaluation of physical-mechanical properties of ceramic made from zirconia. The RUS method has the advantage of being rapid, has a good accuracy and can be used in quality control of the object. © 2016 Taylor and Francis Group, London

Monitoring techniques for nanocrystalline stabilized zirconia from some medical prosthesis

International audienceThe paper proposes the investigation of influence of doping with Ce ions to the phase stability and mechanical properties of zirconium dioxide. For this investigation, we used X-ray and neutron diffraction, electron microscopy and microstructure characterization, including Resonant Ultrasound Spectroscopy (RUS) for nondestructive evaluation of physical-mechanical properties of ceramic made from zirconia. The RUS method has the advantage of being rapid, has a good accuracy and can be used in quality control of the object. © 2016 Taylor and Francis Group, London

Monitoring techniques for nanocrystalline stabilized zirconia from some medical prosthesis

International audienceThe paper proposes the investigation of influence of doping with Ce ions to the phase stability and mechanical properties of zirconium dioxide. For this investigation, we used X-ray and neutron diffraction, electron microscopy and microstructure characterization, including Resonant Ultrasound Spectroscopy (RUS) for nondestructive evaluation of physical-mechanical properties of ceramic made from zirconia. The RUS method has the advantage of being rapid, has a good accuracy and can be used in quality control of the object. © 2016 Taylor and Francis Group, London