Magnetoflicker noise in Na and K

Abstract

It is shown that a physical model put forward to explain the induced-torque anomalies observed by Schaefer and Marcus in single-crystal spheres of Na and K requires the existence of a new type of $\frac{1}{f}$ flicker noise in large magnetic fields. A quantitative theory of this effect is developed. The mean-square noise voltage is proportional to $\frac{I^2{R}_0^2{B}^3\Delta f}{f}$, where $I$ is the current, $R_0$ is the zero-field resistance, $B$ is the magnetic field, and $\Delta f$ is the bandwidth. For a convenient experiment the noise could be as large as ${(1\mathrm{}\times {10}^{-6\mathrm{}}\mathrm{V})}^2$, 13 orders of magnitude greater than Johnson noise. Experimental study is recommended to illuminate further the perplexing magnetoconductivity properties of Na and K.