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The effect of monovalent impurities on KCl low‐temperature specific heat
Author(s) -
Augst G. R.,
Kvavadze K. A.
Publication year - 1975
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220720111
Subject(s) - impurity , ion , atmospheric temperature range , doping , absorption (acoustics) , specific heat , materials science , range (aeronautics) , chemistry , analytical chemistry (journal) , condensed matter physics , thermodynamics , composite material , physics , chromatography , optoelectronics , organic chemistry
An enhancement of the specific heat of KCl crystals doped with Ag + and Na + impurities in the temperature range 5 to 30 K is observed. A comparison of the experimental results with the theory shows that in the case of Ag + the force constants (FC) are weakened by four times. The established quasi‐local frequency (QLF) is close to that found in experiments of infrared absorption. The anomalous increase of the low‐temperature specific heat of the KCl crystals with light substitutional Na + impurities are ascribed to the vibration of isolated ions with FC weakened 2.5 times. The results of the investigation of KCl crystals with monovalent impurities show that the curve shape of the specific‐heat excess differs in accordance with FC strengthening or weakening.