Structural elucidation and iron oxidation states in situ formed β‐Ca3(PO4)2/α‐Fe2O3 composites |
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| Authors: | Ponnusamy Nandha Kumar Sandeep K Mishra Sanjeevi Kannan |
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| Affiliation: | Centre for Nanoscience and Technology, Pondicherry University, Puducherry, India |
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| Abstract: | A detailed structural analysis on the in situ synthesized β‐Ca3(PO4)2/α‐Fe2O3 composites is demonstrated. Compositional ratios, the influence and occupancy of iron at the β‐Ca3(PO4)2 lattice, oxidation state of iron in the composites are derived from analytical techniques involving XRD, FT‐IR, Raman, refinement of the powder X‐ray diffraction and X‐ray photoelectron spectroscopy. Iron exists in the Fe3+ state throughout the investigated systems and favors its occupancy at the Ca2+(5) site of β‐Ca3(PO4)2 until critical limit, and thereafter crystallizes as α‐Fe2O3 at ambient conditions. Fe3+ occupancy at the β‐Ca3(PO4)2 lattice yields a Ca9Fe(PO4)7 structure that is isostructural with its counterpart. A strong rise in the soft ferromagnetic behavior of β‐Ca3(PO4)2/α‐Fe2O3 composites is obvious that depends on the content of α‐Fe2O3 in the composites. Overall, the diverse level of iron inclusions at the calcium phosphate system with a Ca/P ratio of 1.5 yields a structurally stable β‐Ca3(PO4)2/α‐Fe2O3 composites with assorted compositional ratios. |
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| Keywords: | composites magnetic structure α ‐Fe2O3 β ‐Ca3(PO4)2 |
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