MARTINELLI , Alberto

Single-phase sHo0.50Ca0.50dMnO3 has been successfully prepared by means of solid state reaction at high temperature. Its crystal structure, as well as those of Cr-doped samples (Ho1−xCax)(Mn1−yCry)O3, has been refined by the Rietveld method, using X-ray powder diffraction data. All the examined compounds crystallize in the Pnma space group with...

The combustion of vanadium-carbon powder mixtures at low O2 pressure was studied. The reaction was ignited toy induction heating; a wave-front was observed propagating throughout the reactants. The combustion temperature, Tc, was higher than the melting point of V and metal particles melted and coalesced during combustion. The analysis of the...

The pseudo-binary TiO2–FeSbO4 system was investigated by means of thermogravimetric analysis below 1673 K in O2. Rutile-type solid solutions were synthesised at 1373 K in O2 by means of a solid state reaction between the two pure end members TiO2 (rutile) and FeSbO4 mixed in stoichiometric amounts. Thermal stability of the (Ti2xFe1−xSb1−x)O4...

Thermal stabilities of the rutile-type (Sn2xFe1xSb1x)O4 solid solutions with x 0:5 were investigated by TG–DTA in flowing O2 up to 1673 K. After thermal analysis the samples were characterised by means of powder X-ray diffraction analysis (XRD), optical and scanning electron microscopy (SEM) observation and electron dispersive spectrometry...

Orthorhombic LaErO3 and cubic (La0.5 Ln 0.5)2O3 oxides (Ln: Er, Dy) were examined by neutron powder diffraction between 1.5 K and 15 K in order to investigate their crystallographic and magnetic structures. At 1.5 K both LaErO3 and (La0.5Er0.5)2O3 display a magnetic moments ordering, whereas for (La0.5Dy0.5)2O3 only short range magnetic...

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By applying the combustion synthesis technique on stoichiometric elemental powder compacts and subsequent suitable isothermal annealing treatements, the following three crystalline compounds were prepared: MgxCyNi3, MgNi2(C), Mg2Ni(C). The samples were analyzed by means of X-ray and synchrotron powder diffraction and scanning electron...

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The crystal and magnetic structures of LaCrO3 and La(Cr0.90Ti0.10)O3 have been investigated between 5 and 350 K by means of neutron powder diffraction and DC magnetic measurements. Both compounds are characterized by an antiferromagnetic Gx-type ordering at low temperature. Structural features suggest the occurrence of Ti in the tetra-valent...

The crystal and magnetic structures of (Tm0.50Ca0.50)MnO3 and (Lu0.50Ca0.50)MnO3 have been investigated between 5 K and 300 K by means of high resolution neutron powder diffraction followed by Rietveld refinement and dc magnetic measurements. During cooling orbital ordering at the Mn sublattice takes place at TOO280 K in both compounds,...

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The crystal structure of SmFeAs(O0.93F0.07) has been investigated under high pressure (up to 9 GPa) by means of synchrotron powder diffraction analysis followed by Rietveld refinement. The bulk modulus was calculated (K0 = 103 GPa) using a 3rd order Birch–Murnaghan equation of state and resulted in quite good agreement with theoretical...

The ground state magnetic behaviour of Ce2(Pd0.8Ag0.2)2In and Ce2(Pd0.5Ag0.5)2In, found in the ferromagnetic branch of Ce2Pd2In, has been investigated by neutron powder diffraction at low temperature. Ce2(Pd0.8Ag0.2)2In is characterized by a ferromagnetic structure with the Ce moments aligned along the c-axis and values of 0.96(2) µ B. The...

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The reaction between Fe2O3 (hematite) and Sb2O3 leading to the formation of the rutile-type compound FeSbO4 was analysed by means of DTA and TG, performed under various O-2 partial pressures up to 1673 K. The reaction products were identified by means of XRD analysis. Three transformations occur in the analysed temperature range: 1. oxidation...

Magnetization measurements and neutron powder diffraction analyses followed by Rietveld refinement have been carried out in order to investigate the magnetic structures of LaYbO3 and LaHoO3. Both compounds exhibit a negative thermal expansion along the a and b axes. In LaYbO3 Yb3+ spins order at 2.4 K according to a FyGz-type structure,...

The solubility in the solid state was investigated for the pseudo-binary system SnO2—(FeSb)O4 at high temperature. Stoichiometric amounts of pure SnO2 and (FeSb)O4 powders were mixed and reacted in air at 1373 K. Solid state solubility was ascertained in the whole compositional range at high temperature, whereas at low temperature a miscibility...

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