Hydrothermal synthesis and structural investigation of perovskite-like mixed oxides of manganese with tungsten or tellurium

Specific structure of perovskite compounds provides them with various interesting properties which vary from magnetic and electric properties to magnetic frustration and half-metallicity. Since it is hard to stabilize Mn3+ cation in solid form, it is important to use solution chemistry methods. Sr3Mn2(W/Te)O9 triple perovskites have been prepared by means of hydrothermal method with sodium hydroxide as mineralizer and ethanol as buffering agent. Since the high spin 6-coordinated Mn3+ cation and Fe3+ cation have the same values of ionic radius (0.645 Å), it is reasonable to expect similar structure of Sr3Mn2(W/Te)O9 and corresponding Sr3Fe2(W/Te)O9 compounds [1, 2]. It is important to find suitable synthesis route for stabilization of desired oxidation state of transition metal cation. Stabilization of cations in solution and synthesized compounds itself have been investigated by electrochemical measurements. Structural characterization has been done by X-ray powder diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected area electron diffraction (SAED), thermogravimetric analysis (TGA) and unpolarized Raman spectroscopy, while their magnetic properties have been determined using SQUID measurements. Similar research has already been done with tellurium- and tungsten- based perovskites. In this research the advances of solution chemistry methods (bottom up approach), over the solid state routes towards the synthesis of complex perovskite structures will be presented.