Photoacoustic detection of FMR depth profiles

Depth profiles of ferromagnetic layered samples were studied with photoacoustically detected ferromagnetic resonance. Results obtained from recorder tapes and from a prepared nickel-iron sandwich are reported. Two different procedures based on frequency and phase resolved measurements were used to deconvolute the layered structure of the ferromagnetic samples. The depth resolution which is a function of the thermal diffusivity of the material and of the modulation frequency was as low as 1μm in the case of the ferromagnetic tapes.