Provider: - Institution: - Data provided by Europeana Collections- Izvršena su strukturna istraživanja nanokristalnih uzoraka cinkovoga aluminata (ZnAl2O4) dopiranoga s 0-11,7 at.% Mn2+, uzoraka ZnAl2O4 dopiranoga s 0-11,6 at.% Ti4+, uzoraka barijevoga aluminata (BaAl2O4) dopiranoga s 0-8,7 at.% Eu3+ i uzoraka BaAl2O4 dopiranoga s 0-6,3 at.% Cr3+ kako bi se ispitao mehanizam ugradnje tih dopanada u ovisnosti o njihovom oksidacijskom stupnju i udjelu. Dopirani uzorci ZnAl2O4 priređeni su metodom sol-gel, a dopirani uzorci BaAl2O4 priređeni su hidrotermalnom metodom. Svi uzorci ispitani su prvenstveno pomoću rentgenske difrakcije. Rietveldovom metodom su utočnjene njihove kristalne strukture, te je ispitana i njihova mikrostruktura. Pri dopiranju cinkovoga aluminata kation Mn2+ inducira pojavu inverzne spinelne strukture cinkovoga aluminata, dok se kation Ti4+ ugrađuje isključivo na oktaedarsko mjesto strukture ZnAl2O4 zamjenjujući kation Al3+. Pri dopiranju barijevoga aluminata kation Eu3+ zamjenjuje Ba2+ s koordinacijom 9, dok kation Cr3+ samo u malom udjelu zamjenjuje Al3+ u jednom od AlO4 tetraedara strukture polaznog aluminata. Pored bitnog utjecaja na strukturu polaznih aluminata, ispitani slučajevi dopiranja imali su i znatan utjecaj na mikrostrukturu aluminata djelujući kao defekti kristalne rešetke.- Structural studies of nanocrystalline samples of zinc aluminate (ZnAl2O4) doped with 0-11.7 at.% Mn2+, samples of ZnAl2O4 doped with 0-11.6 at.% Ti4+, samples of barium aluminate (BaAl2O4) doped with 0-8.7 at.% Eu3+ and samples of BaAl2O4 doped with 0-6.3 at.% Cr3+ have been performed in order to examine the dependence of dopand incorporation mechanism on its oxidation state and doping level. Doped ZnAl2O4 samples were prepared by the sol-gel method, while doped BaAl2O4 samples were prepared by the hydrothermal method. They were examined by X-ray powder diffraction. Crystal structures of samples were refined by the Rietveld method and their microstructure was determined simultaneously. Manganese doping of zinc aluminate caused an appearance of partial inverse spinel structure in zinc aluminate, Mn2+ occupying both tetrahedral and octahedral sites of the spinel structure. In doping, cation Ti4+ incorporated in the octahedral site of ZnAl2O4 structure solely, substituting for Al3+. In doping of BaAl2O4 cation Eu3+ substitutes for 9-coordinated Ba2+, while only a small content of Cr3+ substitutes for Al3+ in one of the available AlO4 tetrahedra, respectively. Besides the strong influence on structure of zinc aluminates and of barium aluminates, doping also influences their microstructure, because the dopand cations act as defects in the crystal structure lattice.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana