Characterization of electrodeposited thin layers of magnetic alloys by Mössbauer spectroscopy

Rare earth and transition metal alloys are interesting magnetic materials for applications in the field of magnetooptical memories. We describe the preparation of Dy/Fe alloys by electrodeposition using a pulsed galvanostatic process. Samples were characterized by Mössbauer spectroscopy. Thin layers obtained with short electrolysis pulses (0.1 s) give a Mössbauer spectrum analysed as the sum of two subspectra: the first corresponds to a spectrum originating from very small sized particles of Fe and the second is attributed to a Dy/Fe phase. Longer electrolysis pulses (1 s) give samples whose spectrum is also the sum of two subspectra: the first is attributed to metallic Fe with an extended particle-size distribution while the second is attributed to a Fe/Dy alloy. Mössbauer spectroscopy was found useful in determining the best electrolysis parameters leading to domains of uniform magnetization with high coercive fields.