DC Detection of Ferromagnetic Resonance in Thin Nickel Films

Abstract

Experimental work on nickel films is presented which verifies the theory that the dc voltages accompanying ferromagnetic resonance in thin metallic films arise from the nonlinear electrical conduction terms in ferromagnetics involving the extraordinary Hall effect and the magnetoresistive anisotropy. Each of a group of four nickel films of different thickness was subjected to microwave pulses in well-defined configurations of local microwave fields, as required for quantitative comparison of theory and experiment, and the resulting dc pulses were studied as a function of applied magnetic field and of microwave power and field configuration. The results lead to a complete specification of the films' electrical and magnetic properties at microwave frequencies. The films studied showed low magnetization but similar relaxation times compared to bulk nickel. The microwave resistivity is usually larger than at dc and complex. The magnetoresistive anisotropy has its bulk value, while the extraordinary Hall constant is very large.