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

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

doi:10.1016/j.ssc.2005.03.063

Synthesis and characterization of Na_0.3RhO₂·0. 6H₂O - A semiconductor with a weak ferromagnetic component

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

Research output: Contribution to journal › Article › peer-review

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Abstract

We have prepared the oxyhydrate Na_0.3RhO₂·0. 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 Na_0.3(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 Na_0.3RhO ₂·0.6H₂O (T<300) reveal insulating and semi-conducting behavior with activation gaps of 134 and 7.8 meV, respectively. Both Na_0.3RhO₂·0.6H₂O 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 Na_0.3RhO₂·0.6H₂O 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 μ_B for NaRhO₂ and 0.8×10^-1 μ_B for Na_0.3RhO₂·0.6H₂O.

Original language	English
Pages (from-to)	51-56
Number of pages	6
Journal	Solid State Communications
Volume	135
Issue number	1-2
DOIs	https://doi.org/10.1016/j.ssc.2005.03.063
Publication status	Published - 2005 Jul

Bibliographical note

Funding Information:
Research at Brookhaven National Laboratory is supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Science and the Division of Chemical Sciences under contract DE-AC02-98CH10886. Research carried out in part at the NSLS at BNL is supported by the US DOE (DE-Ac02-98CH10886 for beam line X7A).

All Science Journal Classification (ASJC) codes

Chemistry(all)
Condensed Matter Physics
Materials Chemistry

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10.1016/j.ssc.2005.03.063

Cite this

@article{e6277480b70e43f7811774998cedafa4,

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

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.",

author = "S. Park and K. Kang and W. Si and Yoon, {W. S.} and Y. Lee and Moodenbaugh, {A. R.} and Lewis, {L. H.} and T. Vogt",

note = "Funding Information: Research at Brookhaven National Laboratory is supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Science and the Division of Chemical Sciences under contract DE-AC02-98CH10886. Research carried out in part at the NSLS at BNL is supported by the US DOE (DE-Ac02-98CH10886 for beam line X7A).",

year = "2005",

month = jul,

doi = "10.1016/j.ssc.2005.03.063",

language = "English",

volume = "135",

pages = "51--56",

journal = "Solid State Communications",

issn = "0038-1098",

publisher = "Elsevier Limited",

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TY - JOUR

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, Y.

AU - Moodenbaugh, A. R.

AU - Lewis, L. H.

AU - Vogt, T.

N1 - Funding Information: Research at Brookhaven National Laboratory is supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Science and the Division of Chemical Sciences under contract DE-AC02-98CH10886. Research carried out in part at the NSLS at BNL is supported by the US DOE (DE-Ac02-98CH10886 for beam line X7A).

PY - 2005/7

Y1 - 2005/7

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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