Synthesis, electrical transport and Mössbauer spectroscopy study of the layered iron tellurides Fe1.1−xNixTe

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Abstract

The synthesis, characterization, electrical transport and Mössbauer spectroscopy study of the layered iron telluride series Fe1.1−xNixTe (x = 0, 0.02, 0.04, 0.08, 0.12) have been carried out. X-ray characterization studies show that the Ni substituted compounds exhibit the tetragonal PbO-type structure similar to the pristine compound Fe1.1Te, but with a reduction of the unit cell volume. Micro-structural analysis using combined scanning electron microscopy and energy-dispersive X-ray spectroscopy reveal plate like morphology and fine grain sizes. The Ni contents are in agreement with the nominal composition. Mössbauer spectroscopic studies indicate significant changes in the local symmetry at the iron site upon substitution, including a more symmetric FeTe4 tetrahedron. It is inferred from the resistivity study in the range 300–4.2 K that Ni substitution leads to the suppression of the first order phase transition observed in Fe1.1Te. However superconductivity is not observed in the substituted compounds unlike in the case of anionic doping reported earlier.

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