Structural study and physical properties of a new phosphate KCuFe(PO4)2 |
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Authors: | Abdessalem Badri María Luisa López Alain Wattiaux |
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Institution: | a UR Matériaux Inorganiques, Faculté des Sciences, 5019 Monastir, Tunisie b Departamento de Química Inorgánica I, Facultad de Ciencias Químicas, Universidad Complutense, 28040 Madrid, Spain c Institut de Chimie de la Matière Condensée de Bordeaux, CNRS,Université de Bordeaux I, 87 Avenue du Dr. A. Schweitzer, 33608 Pessac-Cedex, France |
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Abstract: | Single crystals of a new phosphate KCuFe(PO4)2 have been prepared by the flux method and its structural and physical properties have been investigated. This compound crystallizes in the monoclinic system with the space group P21/n and its parameters are: a=7.958(3) Å, b=9.931(2) Å, c=9.039(2) Å, β=115.59(3)° and Z=4. Its structure consists of FeO6 octahedra sharing corners with Cu2O8 units of edge-sharing CuO5 polyhedra to form undulating chains extending infinitely along the b-axis. These chains are connected by the phosphate tetrahedra giving rise to a 3D framework with six-sided tunnels parallel to the 101] direction, where the K+ ions are located. The Mössbauer spectroscopy results confirm the exclusive presence of octahedral Fe3+ ions. The magnetic measurements show the compound to be antiferromagnetic with Cm=5.71 emu K/mol and θ=−156.5 K. The derived experimental effective moment μex=6.76μB is somewhat higher than the theoretical one of μth=6.16μB, calculated taking only into account the spin contribution for Fe3+ and Cu2+ cations. Electrical measurements allow us to obtain the activation energy (1.22 eV) and the conductivity measurements suggest that the charge carriers through the structure are the potassium cations. |
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Keywords: | Phosphate X-ray diffraction Mö ssbauer spectroscopy Magnetic susceptibility Electrical measurements |
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