Studies on the Superconductivity in the System (Li 1-x M x )Ti 2 O 4 (M=Mg, Be) with the Spinel Structure

Kenji Kawaguchi, Etsuo Akiba, Shigemitsu Shin, Naruaki Tojima

Research output: Contribution to journalArticle

Abstract

The system (Li 1-x M x )Ti 2 O 4 (M=Mg, Be) with the spinel structure was prepared by firing twice a mixture of the component oxides, i.e., Li 2 O, MgO, BeO, Ti 2 O 3 , and TiO 2 at 1073K for 12 h in vacuo(ca. 10 -5 Torr). The lattice constants were obtained by the powder X-ray diffractometry whereas the molar fraction of Ti 3+ ions in the total Ti atoms, i.e., f (%) was determined by thermogravimetry. The critical temperatute Tc(K, mid-point) was obtained by using a usual four-probe resistivity measurement in the range of 300 K to ca. 2 K. As a result, the cubic lattice constant a(A) of the system linearly increased as the molar ratio f increased. However, it was found that Be 2+ with a much smaller ionic radius than that of Li + can hardly replace the Li + site of the spinel structure, as implied from the plots of the lattice parameter a and the chemical composition x. The highest Tc was observed at f=ca. 50 % in the composition Li 1+x Ti 2-x O 4 , and the Tc suddenly decreased as either the molar ratio f or the lattice constant a decreased. On the other hand, the Tc of the composition (Li 1-x Mg x )Ti 2 O 4 gradually decreased as either the molar ratio f or lattice constant a increased.

Original languageEnglish
Pages (from-to)551-554
Number of pages4
JournalJournal of the Japan Society of Powder and Powder Metallurgy
Volume36
Issue number5
DOIs
Publication statusPublished - Jan 1 1989

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Superconductivity
Lattice constants
Chemical analysis
Powders
Oxides
X ray diffraction analysis
Thermogravimetric analysis
spinell
Ions
Atoms

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry

Cite this

Studies on the Superconductivity in the System (Li 1-x M x )Ti 2 O 4 (M=Mg, Be) with the Spinel Structure . / Kawaguchi, Kenji; Akiba, Etsuo; Shin, Shigemitsu; Tojima, Naruaki.

In: Journal of the Japan Society of Powder and Powder Metallurgy, Vol. 36, No. 5, 01.01.1989, p. 551-554.

Research output: Contribution to journalArticle

Kawaguchi, Kenji ; Akiba, Etsuo ; Shin, Shigemitsu ; Tojima, Naruaki. / Studies on the Superconductivity in the System (Li 1-x M x )Ti 2 O 4 (M=Mg, Be) with the Spinel Structure In: Journal of the Japan Society of Powder and Powder Metallurgy. 1989 ; Vol. 36, No. 5. pp. 551-554.
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abstract = "The system (Li 1-x M x )Ti 2 O 4 (M=Mg, Be) with the spinel structure was prepared by firing twice a mixture of the component oxides, i.e., Li 2 O, MgO, BeO, Ti 2 O 3 , and TiO 2 at 1073K for 12 h in vacuo(ca. 10 -5 Torr). The lattice constants were obtained by the powder X-ray diffractometry whereas the molar fraction of Ti 3+ ions in the total Ti atoms, i.e., f ({\%}) was determined by thermogravimetry. The critical temperatute Tc(K, mid-point) was obtained by using a usual four-probe resistivity measurement in the range of 300 K to ca. 2 K. As a result, the cubic lattice constant a(A) of the system linearly increased as the molar ratio f increased. However, it was found that Be 2+ with a much smaller ionic radius than that of Li + can hardly replace the Li + site of the spinel structure, as implied from the plots of the lattice parameter a and the chemical composition x. The highest Tc was observed at f=ca. 50 {\%} in the composition Li 1+x Ti 2-x O 4 , and the Tc suddenly decreased as either the molar ratio f or the lattice constant a decreased. On the other hand, the Tc of the composition (Li 1-x Mg x )Ti 2 O 4 gradually decreased as either the molar ratio f or lattice constant a increased.",
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