High-frequency giant magnetoresistance measurement to study the dynamics of a micron-scale spin-valve sensor

Abstract

We report on the study of the magnetization dynamic of a single micrometric spin-valve element by high-frequency giant magnetoresistance measurement. We have combined transport measurements in the microwave range and large band ferromagnetic resonance with microantennas. The spin valve is used as an in situ demodulator to probe the individual dynamics of each layer and the relative phase of their oscillations. We deduce the conditions for coupling the hard and free layer dynamics and show the influence of a static magnetic configuration on the sensitivity of spin valves in the microwave range. This work offers a different approach for studying the dynamics of single isolated micron-sized systems. © 2008 The American Physical Society.