Preparation of NaC60 and its physical properties revealed by differential scanning calorimetry, 23Na-NMR and ESR

Takabayashi, Yasuhiro; Kubozono, Yoshihiro; Kashino, Setsuo; Iwasa, Yoshihiro; Taga, S.; Mitani, Tadaoki; Ishida, Hiroyuki; Yamada, Kazuhiko

doi:10.1016/s0009-2614(98)00394-7

Cited by 9 publications

(7 citation statements)

References 12 publications

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“…This is in agreement with X-ray diffraction studies where Rietveld fits showed that Na 4 C 60 arranges in a body-centered monoclinic unit cell with sodium atoms in the tetrahedral interstitial sites. The center of gravity of the central line in the NMR spectrum is [21] and NaC 60 [25], but relatively different from the shifts found in Na 2 C 60 and Na 6 C 60 [20].…”

Section: Resultscontrasting

confidence: 60%

7Li and 23Na MAS solid state NMR studies of Na4C60 and Li4C60

Wågberg

Johnels

2006

Journal of Physics and Chemistry of Solids

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Section: Resultscontrasting

confidence: 60%

7Li and 23Na MAS solid state NMR studies of Na4C60 and Li4C60

Wågberg

Johnels

2006

Journal of Physics and Chemistry of Solids

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“…Figures 1͑a͒, 1͑b͒, and 1͑c͒ show the ESR spectra for Na 2 C 60 at 295 and 2 K, and the ESE spectrum observed in the field scan at 20 K, respectively. The spectrum at 295 K could be reproduced by using two Lorentzian functions with the peak-to-peak line widths ⌬H pp of 11.5 and 2.1 G. The spectrum was similar to that of NaC 60 , which was composed of two components with ⌬H pp of 12.6 and 2.0 G at 263 K. 5 These parameters were determined by a least-squares fitting with two Lorentzian functions. The ESR spectra were measured in a cooling process from 295 to 2 K, and in a heating process from 295 to 350 K. The ESE spectrum shown in Fig.…”

Section: Resultsmentioning

confidence: 91%

“…The structure and physical properties of Na-doped C 60 (Na x C 60 ) are of very interest because they are different from those of the other alkali-doped C 60 ͑A x C 60 , A:K, Rb, and Cs͒. [1][2][3][4][5][6][7] The superconducting phase has not yet been found for Na x C 60 ; Na 3 C 60 , which exhibits an face-centered cubic ͑fcc͒ structure (Fm3 m) is not a superconductor, 1 contrary to Rb 3 C 60 and K 3 C 60 . Na x C 60 with xϾ6 can exist because of a small ionic radius of Na ϩ ion; Yildirim et al prepared Na 9.7 C 60 with an fcc structure (Fm3 ).…”

Section: Introductionmentioning

confidence: 99%

“…1,8 Furthermore, we recently reported the existence of NaC 60 with an fcc structure. 5 Early studies on the physical properties of Na x C 60 showed that these are insulating, 10,11 except for one that reported a metallic behavior for Na 2 C 60 from the photoemission spectra. 12 Recently, Yildirim et al reported the metallic behavior for Na 6 C 60 in the temperature region from 100 to 300 K on the basis of the spin susceptibility spin determined from electron spin resonance ͑ESR͒.…”

Section: Introductionmentioning

confidence: 99%

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Metal-insulator transition at 50 K inNa2C60

et al. 1999

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Temperature dependence of electron spin resonance in Na 2 C 60 was studied in a temperature range from 2 to 350 K. It was shown that Na 2 C 60 was metallic above 50 K and had a metal-insulator transition at 50 K. The center frequency for the Hg͑2͒ Raman mode in Na 2 C 60 at 298 K was close to those in the metallic Rb 3 C 60 , K 3 C 60 , and Cs 3 C 60 , while the linewidth was close to that in the metallic but nonsuperconducting Cs 3 C 60. The Hg͑2͒ mode showed a large blueshift and narrowing at 50 K. The center frequency and the linewidth in the low-temperature region from 50 K were almost the same as those in the insulating C 60 and Rb 6 C 60 , which showed the metal-insulator transition at 50 K in Na 2 C 60. The origin of this metal-insulator transition was discussed in terms of the electron-phonon interaction ͑Jahn-Teller effect͒ and the electron-electron interaction ͑Mott-Hubbard picture͒. ͓S0163-1829͑99͒04123-5͔

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“…30 It should be noted that the sodium compounds are distinctive among all types of carbon intercalates for their "nonstandard" behavior. [36][37][38][39][40] We mentioned anomalies in the structural data above, and below we shall examine magnetic anomalies detected during our spectroscopic studies of sodium fullerides and, especially, Na 3 C 60 obtained from toluene, which stands out from the general tendency. [36][37][38][39][40] We mentioned anomalies in the structural data above, and below we shall examine magnetic anomalies detected during our spectroscopic studies of sodium fullerides and, especially, Na 3 C 60 obtained from toluene, which stands out from the general tendency.…”

Section: A Homofullerides Of the Alkali Metalsmentioning

confidence: 95%

Superconductivity and spectroscopy of homo- and heterofullerides of alkali metals and thallium

Kulbachinskii

Булычев

Кытин

et al. 2011

Low Temperature Physics

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Communication: Molecular dynamics simulations of the interfacial structure of alkali metal fluoride solutions Intercalation of heavy alkali metals (K, Rb and Cs) in the bundles of single wall nanotubes AIP Conf.Liquid alloys of metals with mercury ͑amalgams͒ are used to synthesize the fullerides A n Hg x C 60 ͑A=K,Rb,Cs; n =2;3; x Ͻ 1͒, A n Tl m Hg x C 60 ͑A=K,Rb,Cs; n =1;2; m = 0.25-2; x Ͻ 1͒, and Na n C 60 ͑n=2,3͒. The samples are studied by x-ray diffraction, nuclear magnetic resonance, electron paramagnetic resonance, Raman scattering, and differential scanning calorimetry. The Na n C 60 ͑n=2,3͒ fullerides are not superconducting. Structural phase transitions are observed in them as the temperature is varied. K 2 Hg x C 60 is a superconductor with a transition temperature T c = 22 K, while K 3 Hg x C 60 is not superconducting. Rb n Hg x C 60 ͑n=2,3͒ are superconductors with T c = 24-25 K. The cesium fullerides with an assumed composition of Cs n Hg x C 60 ͑n=1-3͒ are either polymers ͑n=2,3͒ or crystallize in a rhombic lattice, but none are superconducting. A maximum T c = 22 K is observed in the K 2 Tl m Hg x C 60 fulleride with a thallium concentration m = 0.5. Cs n Tl m Hg x C 60 ͑n=1-3; m=1,2͒ is not superconducting, but KCsTlC 60 produced by means of exchange reactions with TlCl is a superconductor with T c = 21.7 K.

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Preparation of NaC60 and its physical properties revealed by differential scanning calorimetry, 23Na-NMR and ESR

Cited by 9 publications

References 12 publications

7Li and 23Na MAS solid state NMR studies of Na4C60 and Li4C60

7Li and 23Na MAS solid state NMR studies of Na4C60 and Li4C60

Metal-insulator transition at 50 K inNa2C60

Superconductivity and spectroscopy of homo- and heterofullerides of alkali metals and thallium

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