Thermophysical study of structural phase transitions in Na0.95Li0.05NbO3 solid solution

• Published in: Bulletin of the Russian Academy of Sciences. Physics Vol. 80; no. 9; pp. 1046 - 1050
• Main Authors: Gorev, M. V., Bondarev, V. S., Raevskaya, S. I., Flerov, I. N., Malitskaya, M. A., Raevskii, I. P.
• Format: Journal Article
• Language: English
• Published: New York Allerton Press 01-09-2016; Springer Nature B.V
• Subjects: Anomalies; Hadrons; Heat treating; Heat treatment; Heavy Ions; Lithium niobates; Nuclear Physics; Phase transitions; Physics; Physics and Astronomy; Proceedings of the VIII (XIII) International Seminar on the Physics of Ferroelastics; Solid solutions; Thermal expansion
• ISSN: 1062-8738; 1934-9432
• DOI: 10.3103/S1062873816090148

Temperature dependences of specific heat
C
p
(
T
) and coefficient of thermal expansion ;(T) for Na
0.95
Li
0.05
NbO
3
sodium-lithium niobate ceramic samples are investigated in the temperature range of 100–800 K. The
C
p
(
T
) and α(
T
) anomalies at
T
3
= 310 ± 3 K,
T
2
= 630 ± 8 K, and
T
1
= 710 ± 10 K are observed, which correspond to the sequence of phase transitions
N
↔
Q
↔
S
(
R
) ↔
T
2(
S
). The effect of heat treatment of the samples on the sequence of structural distortions was established. It is demonstrated that annealing of the samples at 603 K leads to splitting of the anomaly corresponding to the phase transition
Q
→
R/S
in two anomalies. After sample heating to 800 K, the only anomaly is observed in both the
C
p
(
T
) and ;(T) dependence. Possible mechanisms of the observed phenomena are discussed.