Photothermal characterization of multi-layer magnetic materials

In magnetic media thermal transport properties are sensitive to the large internal field associated with the magnetization. Using photoacoustic detection, we show how measurement of the amplitude of thermal waves traversing a magnetic medium provides a technique with the potential to separate the magnetic characteristics of different layers in a multi-layer structure. The technique is demonstrated by recovering the hysteresis loops of magnetic films in tri-layer structures with thick (100 nm) nonmagnetic capping layers.