gValue of Potassium Conduction Electrons

Abstract

Spin resonance of conduction electrons has been observed near 12 Gc/sec in sheets of vacuum-distilled potassium metal in the temperature range from 1.3°K to room temperature. Linewidths on the order of, or less than, one gauss at liquid-helium temperatures permit an accurate $g$-value determination: $g_{\mathrm{K}}=1.9997\mathrm{}\left(8\right)\mathrm{}\pm 0.0001$. The experimental $g$ shift is in close agreement with values recently calculated by Bienenstock and Brooks neglecting polarization of the ion cores. Variations of line shape and apparent intensity with the orientation of the applied magnetic field relative to the sample plane have been observed at the lowest temperatures.