Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Temperature dependences of the specific heat C and the magnetic susceptibility chi of Na1-xV2O5 single crystals (x = 0, 0.01, 0.02, 0.03, and 0.04) are studied. In NaV2O5, the transition to the spin-gap state (T-c = 34 K) is accompanied by a sharp decrease in chi, while C exhibits a lambda -shaped anomaly. At low temperatures, the specific heat of NaV2O5 is approximated by the sum of phonon similar toT(3) and magnon similar to exp(-Delta /T) contributions, which makes it possible to estimate the Debye temperature Theta (D) = 336 K and the gap in the magnetic excitation spectrum Delta = 112 K. With the departure from stoichiometry, the anomalies observed in the behavior of chi and C are spread and shifted to lower temperatures. The low-temperature specific heat of nonstoichiometric samples is determined by the sum of phonon and magnon components and the contribution due to the presence of defects. The values of magnetic entropy characterizing the phase transitions in Na1-xV2O5 are calculated. (C) 2001 MAIK "Nauka/Interperiodica".