Naslov
Evidence forS=0-type spin pairing in the nonferromagnetic modification ofTDAE−C60

Autori
Arčon, Denis ; Blinc, Robert ; Cevc, Pavel ; Omerzu, Aleš

Izvornik
Physical review. B, Condensed matter and materials physics (1098-0121) 59 (1999), 7; 5247-5251

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
magnetic transition ; single-crystal ; proton NMR ; ferromagnetism

Sažetak
The X-band electron spin resonance (ESR) spectra, the methyl-proton H-1 nuclear magnetic resonance spectra, and the proton spin-lattice relaxation rate T-1(-1) of the nonferromagnetic modification of tetrakis-dimethylamino-ethilene (TDAE)-C-60 have been studied between room temperature and 4 K. The results are compared with those previously obtained for the ferromagnetic modification of TDAE-C-60. The nonferromagnetic modification of TDAE-C-60 shows only a single proton line and an X-band ESR intensity that vanishes below 10 K. The temperature dependencies of the proton spin- lattice relaxation rate and the ESR intensity are characteristic for a system with a S= 0 ground state and a nonzero energy gap between the ground state and the first excited triplet state. The singlet-triplet energy gap is estimated to be of the order of 15 K at T=5 K. The nonferromagnetic modification seems to be metastable and spontaneously transforms to a ferromagnetic modification at room temperature or above

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Interdisciplinarne prirodne znanosti

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