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Title: Structural investigations on Co{sub 3-x}Mn{sub x}TeO{sub 6}; (0 < x ≤ 2); High temperature ferromagnetism and enhanced low temperature anti-ferromagnetism

In the quest of materials with high temperature ferromagnetism and low temperature anti-ferromagnetism, we prepare Co{sub 3-x}Mn{sub x}TeO{sub 6}; (0 < x ≤ 2) solid solutions. Room temperature structural investigations on these solid solutions as a function of Mn concentration using Synchrotron X-ray diffraction (SXRD) and X-ray absorption near edge structure measurements in corroboration with magnetism are presented. Phase diagram obtained from Rietveld Refinement on SXRD data as a function of Mn concentration indicates doping disproportionate mixing of both monoclinic (C2/c) and rhombohedral (R 3{sup ¯}) structure for x < 0.5, while only R 3{sup ¯} structure for x ≥ 0.5. Further, it shows increase in both lattice parameters as well as average transition metal-oxygen (Co/Mn-O) bond lengths for x ≥ 0.5. Co and Mn K-edge XANES spectra reveal that both Co and Mn are in mixed oxidation state, Co{sup 2+}/Mn{sup 2+} and Co{sup 3+}/Mn{sup 3+}. Relative ratios of Co{sup 3+}/Co{sup 2+} and Mn{sup 3+}/Mn{sup 2+} obtained using Linear combination fit decrease with increasing x (for x ≥ 0.5). These structural and spectroscopic evidences are used to provide possible interpretation of the observed paramagnetic to ferromagnetic transition at around 185 K followed by an enhanced antiferromagnetic transition ∼45 K for x = 0.5.
Authors:
; ; ;  [1] ;  [2] ; ; ;  [3]
  1. Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore—452013 (India)
  2. Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai—400085 (India)
  3. Technical Physics Division, Bhabha Atomic Research Centre, Mumbai—400085 (India)
Publication Date:
OSTI Identifier:
22314315
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; ABSORPTION SPECTROSCOPY; ANTIFERROMAGNETISM; CARBON COMPOUNDS; COBALT IONS; CONCENTRATION RATIO; FERROMAGNETISM; LATTICE PARAMETERS; MANGANESE IONS; MONOCLINIC LATTICES; OXYGEN; PARAMAGNETISM; PHASE DIAGRAMS; SOLID SOLUTIONS; SYNCHROTRONS; TEMPERATURE RANGE 0065-0273 K; TEMPERATURE RANGE 0273-0400 K; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY