Determination of Relaxation Times by Magnetoacoustic Measurements in Copper

Experimental and theoretical evidence is presented to support the hypothesis that the amplitudes of observable magnetoacoustic oscillations are to a large extent controlled by collision damping. By fitting experimental data on copper to a simple formula derived from the free-electron theory, we find that the temperature dependence of the electron-scattering rate for belly orbits is given by $(1.\mathrm{}5\pm 0.2)\times {10}^6{T}^3$ for temperatures below about 13 °K. This value is comparable to those obtained by other workers using cyclotron resonance. Although our method needs further theoretical development, we believe it has considerable potential as a tool for investigating scattering processes in metals.