|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1997 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1996 : ¥1,800,000 (Direct Cost : ¥1,800,000)
I.Rare earth dicarbides crystals (RC_2 ; R=La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, and Lu) encapsulated in carbon nanocages or nanotubes are synthesized. A role of an eutectic reaction for the RC_2-C systems giving rise the encapsulation compounds is pointed out. The results are published in Physica B and Carbon.
II.Electrical resistance in pressed samples composed of multiwalled carbon nanotubes is described in terms of Mott's law for three-dimensional (3D) variable range hopping (VRH) conduction. While that in pressed samples of three porous systems composed of carbon nanocages in which LaC_2, CeC_2, or GdC_Z crystals are encapsulated is described in terms of Mott's law for 2D VRH conduction. The low field magnetotransport features support a predicted quantum interference effect on 3D or 2D VRH conduction. The results are published in Applied Physics Letters and Journal of Applied Physics.
III.A systematic study of magnatization curves for CeC_2 crystals encapsulated in carbon nanocages in magnetic fields up to 42 T in the low-temperature antiferromagnetic region revealed a phase transition between an antiferromagnetic and spin-flop state at Hc-3.5T,and that between the spin-flop and paramagnetic state at a particular field Hs<15T.The magnetic phase diagram in the applied field and temperature plane is accurately determined based on the results of Hc (Ta) and Hs (T). The results will be published.
IV. 炭化セリウムを内包するフラレンについて磁化測定を系統的におこなった。反強磁性相からスピンフロップ相、スピンフロップ相から常磁性相への磁場誘起転移を観測し、それらの相図を明かにした。成果は、Applied Physics Lettersに発表予定である。