Local structure determination of Mn2+ in the ABCl3: Mn2+ chloroperovskites by EXAFS and optical spectroscopy

摘要: This work reports the local structure around manganese in ABC&: Mn2+ (A = K, Rb, Cs and B Mg, Ca, Cd, Sr) chloroperovskite series. EXAFS XANES experiments carried out KMgCl,:Mn*+ RbCaCI,: Mn*+ indicate that MnCl distances of MnCl:- complex are 2.51 2.53 A, respectively. These values very similar to those found pure NH,MnCI, perovskite, R 2.525 show variations along series do not follow host lattice. The correlation between these measurements optical excitation spectra allows us estimate Mn-Cl bond for whole with accuracies about 0.002 A. present results compared previous structural data reported ABF,: isomorphous fluorides. role physical properties inorganic com- pounds. A proper microscopic understanding such requires a knowledge impurity; is neighborhood ions, site symmetry distances. In wide band gap insulating crystals, formed by impu- rity ion its nearest neighbors can usually account properties. Apart from ligands their coordination polyhedra which be revealed standard selective techniques as EPR, Raman scattering or spectroscopy, determination still difficult task many doped materials spite continuous improve- ments last few years. particular, this technique has serious limitations impurity concentrations below 1 mol%, well determining metal-ligand better than 0.02A. Due fact, accurate characterization impurities presently known only small number systems.