Calorimetric Measurements at Low Temperatures in Toluene Glass and Crystal
The specific heat of toluene in glass and crystal states has been measured both at low temperatures down to 1.8 K (using the thermal relaxation method) and in a wide temperature range up to the liquid state (using a quasiadiabatic continuous method). Our measurements therefore extend earlier published data to much lower temperatures, thereby allowing to explore the low-temperature “glassy anomalies” in the case of toluene. Surprisingly, no indication of the existence of tunneling states is found, at least within the temperature range studied. At moderate temperatures, our data either for the glass or for the crystal show good agreement with those found in the literature. Also, we have been able to prepare bulk samples of toluene glass by only doping with 2% mol ethanol instead of with higher impurity doses used by other authors.
KeywordsSpecific heat Glass transition Toluene Boson peak Tunneling states
This work has been partially supported by the Spanish Ministry of Economy through Projects FIS2014-54498-R and MAT2014-57866-REDT, and through the “María de Maeztu” Programme for Units of Excellence in R&D (MDM-2014-0377), as well as by the Autonomous Community of Madrid through programme NANOFRONTMAG-CM (S2013/MIT-2850). One of us (M.A.R.) is grateful to Anthony Leggett for discussions and for his suggestion to measure the specific heat of toluene.
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