Observation of Suppressed Interdiffusion in FeRh/FePt-Ta Bilayer Thin Films

FeRh/FePt bilayers on MgO (100) substrates were fabricated by rf-magnetron sputtering, and the magnetic properties and microstructures of the bilayers were studied in terms of Ta addition to the storage layer. Compared to undoped FeRh/FePt bilayers, FeRh/FePt-Ta bilayer films showed improved magnetic properties and lower degree of interdiffusion. The FeRh/FePt-Ta bilayers clearly demonstrated the AFM-FM transition. Reduced interdiffusion by Ta segregation along grain boundaries was speculated to be a possible cause for the observed improvement in magnetic properties when fabricated at high temperature.