NEW IMPURITY EFFECTS IN THERMAL-EXPANSION OF N-14(2)-AR SOLID-SOLUTIONS

Thermal expansion of solid solutions of nitrogen in argon (0.51; 2.24; 4.89% N-14(2)) has been investigated in the temperature range 1-16 K. An impurity contribution da to a linear expansion coefficient has bee n separated. Negative values of Delta alpha at T < 4.3 K for the solut ion with the nitrogen concentration 0.51 % and independence of Delta a lpha on impurity content for two concentrated solutions below 7 K have been found. A qualitative explanation of the peculiarities mentioned has been proposed.