New impurity effect in thermal expansion of ¹⁴N₂-Ar solid solutions

Abstract

Thermal expansion of solid solutions of nitrogen in argon (0.51; 2.24; 4.89% ¹⁴N₂) has been investigated in the temperature range 1-16 K. An impurity contribution Да to a linear expansion coefficient has been separated. Negative values of Δα at T < 4.3 К for the solution with the nitrogen concentration 0.51 % and independence of Δα on impurity content for two concentrated solutions below 7 К have been found. A qualitative explanation of the peculiarities mentioned has been proposed.