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

Journal Article · Thu Aug 21 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4893330· OSTI ID:22314315

Singh, Harishchandra; Ghosh, Haranath; Singh, M. N. ^[1]; Rajput, Parasmani ^[2]; Prajapat, C. L.; Singh, M. R.; Ravikumar, G. ^[3]

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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)

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.

• OSTI ID: 22314315
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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