Synthesis, structure, and properties of selected ZrCuSiAs type pnictide oxides and related compounds

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The proposed project has three key subjects, i. e. (i) improvement of the synthesis conditions for RETPnO materials and explorative synthesis of the systems RE–T–Pn–O and RE–T–Pn–O–Cl including structural investigations, (ii) studies of magnetic, electrical and specific heat data of selected RETPnO phases, and (iii) systematic 57Fe Mößbauer spectroscopic studies of iron containing RE(AE)T2Pn2 and RETPnO phases. The preparative part is indispensable for synthesis of high-quality, X-ray pure samples for physical property measurements. Diverse preparation techniques (arc-melting, induction melting, metal- or salt-flux synthesis) are available. All samples will be studied in detail by powder X-ray diffraction and metallography in combination with EDX. Suitable single crystals will be used for structure refinements. These studies are the prerequisite for the diverse property investigations on well defined samples. 57Fe Mößbauer spectroscopy will systematically be used as a local technique for studying the electronic and magnetic behaviour of the respective materials. Together with theoretical investigations the main goal will be the elucidation of concrete structure-property-relations for the pnictides and pnictide oxides.