Spin Transmission Resonance: Theory and Experimental Results in Lithium Metal

Abstract

The present status of conduction-electron spin resonance in metals is reviewed. We attempt to show that in terms of practical sensitivity, detection by the transmission method (diffusion of oriented spins into a noise-free region) is superior to the usual reflection technique. Theoretical line shape is derived by a simple phase-adding procedure and from Dyson's theory of nonlocal magnetization, and the latter is made to yield a useful expression for signal power in terms of apparatus parameters. The paper contains a description of the apparatus and a discussion of how it might be improved. A method is given whereby one may experimentally determine values of spin relaxation time and conduction-electron mean free path. The latter determination seems to be more direct than that derived from conductivity measurements, and the beginnings of an interesting study are indicated. Theory and apparatus performance are compared with results obtained in lithium.