Non-Debye Excess Heat Capacity and Boson Peak of Binary Lithium Borate Glasses

Yu MATSUDA, Hitoshi KAWAJI, Tooru ATAKE, Yasuhisa YAMAMURA, Shuma YASUZUKA, Kazuya SAITO and Seiji KOJIMA

The non-Debye excess heat capacities of binary lithium borate glasses with different Li2O compositions of x = 8, 14 and 22 (mol%) are investigated to understand origin of the boson peak. The low-temperature heat capacities are measured between 2 and 50 K by a relaxation calorimeter. The experimental non-Debye heat capacities with x = 14 is successfully reproduced using the excess vibrational density of states measured
by inelastic neutron scattering. This finding indicates that the non-Debye heat capacities of lithium borate glasses originate from the excess vibrational density of states measureable by inelastic neutron scattering. Moreover, it is demonstrated that all of the excess heat capacity spectra lie on a single master curve by the scaling using boson peak temperature and intensity.
(J. Non-Cryst. Solids, 357, 534-537 (2011))

Anomalous Lattice Heat Capacity of Orientationally Glassy Crystal of p-Chloronitrobenzene at Low Temperatures

Kazuya SAITO, Hiroji KOBAYASHI, Yuji MIYAZAKI and Michio SORAI

Heat capacities of the ordered and disordered crystalline p-chloronitrobenzene, the latter of which is in glassy state below 245 K, were measured down to 0.3 K. The heat capacity of the disordered state exceeds 5 times of that of the ordered phase at 1 K. Temperature dependence of the heat capacity of the disordered state is weaker than that expected by the Debye model. No hump in Cp/T3 was observed for the disordered phase. The behavior is discussed in relation to low-energy excitation in amorphous materials.
(Solid State Commun., 118, 611-614 (2001))

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