The Variation with Magnetic Field and Temperature of the Thermoelectric Properties of Ferromagnetics

It was first shown by Sir Wm. Thomson that a thermocouple may be composed entirely of iron or nickel provided part is in a magnetic field and part not. A survey of the work previously done on this subject and an experimental investigation of a more extended nature than any heretofore have been attempted in order to clear up existing confusion and render the subject more available to theoretical interpretation. Measurements on iron, nickel, cobalt and permalloy from room temperature to above the Curie point indicate that the e.m.f. produced by a magnetic field in these thermocouples is conditioned by (1) the crystal structure and (2) the change in direction of the resulting spins or intrinsic magnetization in separate crystal regions, and that this effect is related to the change in length on magnetization.