Hall effect at the metal–nonmetal transition in metal–ammonia solutions

Abstract

The conductivity and Hall coefficient have been measured for solutions of Li, Na, K, and Cs in liquid NH3 using a double ac method over a concentration range of 1–10 mol% metal (mpm). The conductivities vary from 10−1 to near 104 Ω−1 cm−1 and the Hall coefficients from 10−6 to 10−9 m3C−1 over the 1–10 mpm range. Hall mobilities vary from 10−2 to 100 cm2V−1 s−1 over the same range. The mobility for Na–NH3 solutions shows a maximum at 4 mpm while the others are monotonie. The mobility peak in Na–NH3 solutions appears to be related to the presence of substantial composition fluctuations in that system.