Moessbauer experiments in radio frequency magnetic fields: A method for investigations of nanostructured soft magnetic materials

We apply radio frequency (rf) effects, the sideband and the collapse effect, in the investigation of magnetic properties of nanostructured ferromagnetic alloys. We use the relative intensity of the sidebands in comparison to the central part of the spectrum to determine the relative samples' magnetostriction following successive preparation steps. Recent investigations of nanostructured soft ferromagnetic alloys in rf fields led to the discovery that the collapse in the Moessbauer spectra can become selective and partial. It means that the magnetisation reversal is not fast enough and varies differently in the various phases of the alloy. The application of rf magnetic fields then causes new kinds of rf forced relaxation-type Moessbauer spectra. Experimental results and basic steps in the theoretical understanding are also presented