Magnetic Field Dependence of Induced Torque in Copper

Abstract

Induced torque in copper has been measured for field rotation in a (110) plane at magnetic fields up to 18 kOe. Induced torque from closed orbits tends toward saturation at high fields and is analyzed in terms of two parameters that depend on the magnetoresistance and Hall constant. These parameters are magnetic field dependent and provide a method of determining magnetoresistance. The temperature dependence of induced torque is given for temperatures between 1.4 and 40 °K and is explained by the change in resistivity with temperature. The closed-orbit induced torque is anisotropic. Induced torque in a Cu(Fe) sample is similar to that for pure copper and indicates that impurity scattering is not the major cause of the anisotropy. The anisotropy is attributed to variations in magnetoresistance as determined by the shape and topology of the Fermi surface.