Parametric excitation and mode control using an Oersted field in a NiFe nanowire

Parametric pumping is a nonlinear wave phenomenon and a promising technique for electronic devices based on spin waves, so-called “magnonics”. For parametric excitation, a magnetic nanowire system that has a built-in dc current line to produce an Oersted field is designed, and for spin wave detection, a micro-Brillouin light scattering (μ-BLS) system is used. A spin wave with a frequency of f(sw) = 5.6 GHz is observed when a pumping microwave with a frequency of f(mw) = 11.2 GHz is applied. The wave is found to be of the n = 1 width mode (n is the antinode number), and its mode changes to an edge-localized (or possibly n > 1) mode when the Oersted field (or current) varies. Joule heating effects are not observed in the pumping process. Thus, spin wave mode control by the built-in current would be a convenient and useful method to enhance the efficiency and compatibility in applications of spin-based electronics.