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Abstract
The magnetic and transport properties of three types of polycrystalline materials having perovskite structure are investigated. The first group is concerned with single organic-inorganic hybrids of [(CH₂) (NH₃)₂] FeCl₄, n = 4 and 6 and their parent salts [(CH₂) (NH₃)₂] Cl₂, n = 4 and 6. The effect of Zn- doping of [(CH₂)₆(NH₃)₂] FexZn₁-xCl₄; x = (0.3, 0.5, 0.6, 0.7 and 0.8) on electric and magnetic properties are studied. Powder x-ray diffraction, thermal analysis, ac- conductivity and dielectric measurements of the organic inorganic hybrids (OIHs) were performed at low and high temperatures. Comparison of the magnetic, electrical and structural phase transitions of [(CH₂) (NH₃)₂] FeCl₄, n = 4 and 6 and the Zn doped hybrids are presented. Dielectric constant as well as electric conductivity as related to structure transitions and the effect of doping on the phase changes of [(CH₂)₆(NH₃)₂] FexZn₁₋xCl₄ are discussed. Ac magnetic susceptibility measurements at low temperatures for the Fe - Zn diluted samples indicated spin canted anitferromagnetic interaction for the diluted samples. It shows a shift of the transition temperature as Zn concentration increases in accordance with percolation theory. Another interesting sample of biological and technological importance is the luminescent substituted phosphonium MnBr hybrid, namely [(CH₃) (C₆H₅)₃P]₂. MnBr which is found to be ferroelectric with curie temperature 309.5 K. Structure, magnetic, thermal, dielectric and conductivity of this ferroelectric bi- organic inorganic hybrid is presented