Synthesis and characterization of Na0.3RhO2·0. 6H2O - A semiconductor with a weak ferromagnetic component

S. Park, K. Kang, W. Si, W. S. Yoon, Yongjae Lee, A. R. Moodenbaugh, L. H. Lewis, T. Vogt

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We have prepared the oxyhydrate Na0.3RhO2·0. 6H2O by extracting Na+ cations from NaRhO2 and intercalating water molecules using an aqueous solution of Na2S 2O8. Rietveld refinement, thermogravimetric analysis (TGA), and energy-dispersive X-ray analysis (EDX) reveal that a non-stoichiometric Na0.3(H2O)0.6 network separates layers of edge-sharing RhO6 octahedra containing Rh 3+(4d6, S=0) and Rh4+ (4d5, S=1/2). The resistivities of NaRhO2 and Na0.3RhO 2·0.6H2O (T<300) reveal insulating and semi-conducting behavior with activation gaps of 134 and 7.8 meV, respectively. Both Na0.3RhO2·0.6H2O and NaRhO 2 show paramagnetism at room temperature, however, the sodium-deficient sample exhibits simultaneously a weak but experimentally reproducible ferromagnetic component. Both samples exhibit a temperature-independent Pauli paramagnetism, for NaRhO2 at T>50 K and for Na0.3RhO2·0.6H2O at T>25 K. The relative magnitudes of the temperature-independent magnetic susceptibilities, that of the oxide sample being half that of the oxyhydrate, is consistent with a higher density of thermally accessible electron states at the Fermi level in the hydrated sample. At low temperatures the magnetic moments rise sharply, providing evidence of localized and weakly-ordered electronic spins with effective moment per formula unit values of 2.0×10-1 μB for NaRhO2 and 0.8×10-1 μB for Na0.3RhO2·0.6H2O.

Original languageEnglish
Pages (from-to)51-56
Number of pages6
JournalSolid State Communications
Volume135
Issue number1-2
DOIs
Publication statusPublished - 2005 Jul 1

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Semiconductor materials
Rietveld refinement
Energy dispersive X ray analysis
Network layers
synthesis
electron states
Magnetic moments
Fermi level
Magnetic susceptibility
Oxides
Electron energy levels
Thermogravimetric analysis
Cations
magnetic moments
Positive ions
aqueous solutions
moments
magnetic permeability
cations
Temperature

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry

Cite this

Park, S. ; Kang, K. ; Si, W. ; Yoon, W. S. ; Lee, Yongjae ; Moodenbaugh, A. R. ; Lewis, L. H. ; Vogt, T. / Synthesis and characterization of Na0.3RhO2·0. 6H2O - A semiconductor with a weak ferromagnetic component. In: Solid State Communications. 2005 ; Vol. 135, No. 1-2. pp. 51-56.
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abstract = "We have prepared the oxyhydrate Na0.3RhO2·0. 6H2O by extracting Na+ cations from NaRhO2 and intercalating water molecules using an aqueous solution of Na2S 2O8. Rietveld refinement, thermogravimetric analysis (TGA), and energy-dispersive X-ray analysis (EDX) reveal that a non-stoichiometric Na0.3(H2O)0.6 network separates layers of edge-sharing RhO6 octahedra containing Rh 3+(4d6, S=0) and Rh4+ (4d5, S=1/2). The resistivities of NaRhO2 and Na0.3RhO 2·0.6H2O (T<300) reveal insulating and semi-conducting behavior with activation gaps of 134 and 7.8 meV, respectively. Both Na0.3RhO2·0.6H2O and NaRhO 2 show paramagnetism at room temperature, however, the sodium-deficient sample exhibits simultaneously a weak but experimentally reproducible ferromagnetic component. Both samples exhibit a temperature-independent Pauli paramagnetism, for NaRhO2 at T>50 K and for Na0.3RhO2·0.6H2O at T>25 K. The relative magnitudes of the temperature-independent magnetic susceptibilities, that of the oxide sample being half that of the oxyhydrate, is consistent with a higher density of thermally accessible electron states at the Fermi level in the hydrated sample. At low temperatures the magnetic moments rise sharply, providing evidence of localized and weakly-ordered electronic spins with effective moment per formula unit values of 2.0×10-1 μB for NaRhO2 and 0.8×10-1 μB for Na0.3RhO2·0.6H2O.",
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Synthesis and characterization of Na0.3RhO2·0. 6H2O - A semiconductor with a weak ferromagnetic component. / Park, S.; Kang, K.; Si, W.; Yoon, W. S.; Lee, Yongjae; Moodenbaugh, A. R.; Lewis, L. H.; Vogt, T.

In: Solid State Communications, Vol. 135, No. 1-2, 01.07.2005, p. 51-56.

Research output: Contribution to journalArticle

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T1 - Synthesis and characterization of Na0.3RhO2·0. 6H2O - A semiconductor with a weak ferromagnetic component

AU - Park, S.

AU - Kang, K.

AU - Si, W.

AU - Yoon, W. S.

AU - Lee, Yongjae

AU - Moodenbaugh, A. R.

AU - Lewis, L. H.

AU - Vogt, T.

PY - 2005/7/1

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N2 - We have prepared the oxyhydrate Na0.3RhO2·0. 6H2O by extracting Na+ cations from NaRhO2 and intercalating water molecules using an aqueous solution of Na2S 2O8. Rietveld refinement, thermogravimetric analysis (TGA), and energy-dispersive X-ray analysis (EDX) reveal that a non-stoichiometric Na0.3(H2O)0.6 network separates layers of edge-sharing RhO6 octahedra containing Rh 3+(4d6, S=0) and Rh4+ (4d5, S=1/2). The resistivities of NaRhO2 and Na0.3RhO 2·0.6H2O (T<300) reveal insulating and semi-conducting behavior with activation gaps of 134 and 7.8 meV, respectively. Both Na0.3RhO2·0.6H2O and NaRhO 2 show paramagnetism at room temperature, however, the sodium-deficient sample exhibits simultaneously a weak but experimentally reproducible ferromagnetic component. Both samples exhibit a temperature-independent Pauli paramagnetism, for NaRhO2 at T>50 K and for Na0.3RhO2·0.6H2O at T>25 K. The relative magnitudes of the temperature-independent magnetic susceptibilities, that of the oxide sample being half that of the oxyhydrate, is consistent with a higher density of thermally accessible electron states at the Fermi level in the hydrated sample. At low temperatures the magnetic moments rise sharply, providing evidence of localized and weakly-ordered electronic spins with effective moment per formula unit values of 2.0×10-1 μB for NaRhO2 and 0.8×10-1 μB for Na0.3RhO2·0.6H2O.

AB - We have prepared the oxyhydrate Na0.3RhO2·0. 6H2O by extracting Na+ cations from NaRhO2 and intercalating water molecules using an aqueous solution of Na2S 2O8. Rietveld refinement, thermogravimetric analysis (TGA), and energy-dispersive X-ray analysis (EDX) reveal that a non-stoichiometric Na0.3(H2O)0.6 network separates layers of edge-sharing RhO6 octahedra containing Rh 3+(4d6, S=0) and Rh4+ (4d5, S=1/2). The resistivities of NaRhO2 and Na0.3RhO 2·0.6H2O (T<300) reveal insulating and semi-conducting behavior with activation gaps of 134 and 7.8 meV, respectively. Both Na0.3RhO2·0.6H2O and NaRhO 2 show paramagnetism at room temperature, however, the sodium-deficient sample exhibits simultaneously a weak but experimentally reproducible ferromagnetic component. Both samples exhibit a temperature-independent Pauli paramagnetism, for NaRhO2 at T>50 K and for Na0.3RhO2·0.6H2O at T>25 K. The relative magnitudes of the temperature-independent magnetic susceptibilities, that of the oxide sample being half that of the oxyhydrate, is consistent with a higher density of thermally accessible electron states at the Fermi level in the hydrated sample. At low temperatures the magnetic moments rise sharply, providing evidence of localized and weakly-ordered electronic spins with effective moment per formula unit values of 2.0×10-1 μB for NaRhO2 and 0.8×10-1 μB for Na0.3RhO2·0.6H2O.

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