Change search
ReferencesLink to record
Permanent link

Direct link
On the polyamorphism of fullerite-based orientational glasses.
Show others and affiliations
2005 (English)In: Low Temperature Physics, ISSN 1063-777X, Vol. 31, no 5, 429-444 p.Article in journal (Refereed) Published
Abstract [en]

The dilatometric investigation in the temperature range of 2–28 K shows that a first-order

polyamorphous transition occurs in the orientational glasses based on C60 doped with H2, D2 and

Xe. A polyamorphous transition was also detected in C60 doped with Kr and He. It is observed that

the hysteresis of thermal expansion caused by the polyamorphous transition (and, hence, the transition

temperature) is essentially dependent on the type of doping gas. Both positive and negative

contributions to the thermal expansion were observed in the low-temperature phase of the glasses.

The relaxation time of the negative contribution occurs to be much longer than that of the positive

contribution. The positive contribution is found to be due to phonon and libron modes, whilst the

negative contribution is attributed to tunneling states of the C60 molecules. The characteristic

time of the phase transformation from the low-T phase to the high-T phase has been found for the

C60–H2 system at 12 K. A theoretical model is proposed to interpret these observed phenomena.

The theoretical model proposed, includes a consideration of the nature of polyamorphism in

glasses, as well as the thermodynamics and kinetics of the transition. A model of noninteracting

tunneling states is used to explain the negative contribution to the thermal expansion. The experimental

data obtained is considered within the framework of the theoretical model. From the theoretical

model the order of magnitude of the polyamorphous transition temperature has been estimated.

It is found that the late stage of the polyamorphous transformation is described well by the

Kolmogorov law with an exponent of n = 1. At this stage of the transformation, the two-dimensional

phase boundary moves along the normal, and the nucleation is not important.

Place, publisher, year, edition, pages
2005. Vol. 31, no 5, 429-444 p.
Keyword [en]
Fullerenes, C60, thermal expansion, polyamorphism, orientational glass, hydrogen, Xenon, deuterium, H2, Xe, D2, intercalation, transition temperature, krypton, helium, phonons, tunneling
National Category
Condensed Matter Physics
URN: urn:nbn:se:umu:diva-12437DOI: doi:10.1063/1.1925371OAI: diva2:152108
simultaneous publication in Fizika Nizkikh Temperatur vol. 31, p. 565-84 (2005)Available from: 2008-01-29 Created: 2008-01-29 Last updated: 2011-01-12Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Sundqvist, Bertil
By organisation
Condensed Matter Physics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 71 hits
ReferencesLink to record
Permanent link

Direct link