Growth and characterization of undoped, Sr2+-, and Mn2+-doped ammonium tetrachlorozincate by M. A. Gaffar, A. Abu El-Fadl, and S. Bin Anooz

Crystal Research and Technology

Cryst. Res. Technol. 40, 204 (2005) - Abstract -

Growth and characterization of undoped, Sr²⁺-, and Mn²⁺-doped ammonium tetrachlorozincate

M. A. Gaffar, A. Abu El-Fadl*, and S. Bin Anooz*

Physics Department, School of Science and Engineering, The American University in Cairo, Cairo 11511, Egypt
*Physics Department, Faculty of Science, Assiut University, Assiut 71516, Egypt

Keywords	ammonium tetrachlorozincate, crystal growing, effect of doping
PACS	77-80.-e
DOI	10.1002/crat.200410326

Crystals of ammonium tetrachlorozincate (AZC) undoped and doped with Sr²⁺ or Mn²⁺ in different concentrations were grown by the slow evaporation method from an aqueous solution. The crystal morphology changed considerably by doping. The dopant concentration in the crystals was measured by the atomic absorption technique. Slight changes in the unit cell parameters of AZC after doping with Sr²⁺ or Mn²⁺ have been detected. Optical absorption measurements indicated strong influence of Sr²⁺ and Mn²⁺ doping. The optical energy gap at room temperature decreased continuously with increasing Sr²⁺ and Mn²⁺ concentration but with two different rates. The dc conductivity was also measured as a function of temperature for the undoped and two samples doped with 0.144 Sr²⁺ and 0.191 Mn²⁺ and the results were compared. Positions possibly occupied by Sr²⁺ and Mn²⁺ cations in AZC lattice have been identified.

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