Morphology, structure and magnetic properties of (Tb0.3Dy0.7Fe2)100-xFex nanogranular films produced by ultrashort pulsed laser deposition

Magnetic films were produced by ultrashort pulsed laser deposition (uPLD) using a rotating multitarget of terfenol-D (nominal composition: Tb0.3Dy0.7Fe2) and iron. The composite films obtained have a nanoparticle morphology typical of material produced by the uPLD technique, where each particle retains the stoichiometry of the parent target material. The co-deposition allows the production of (Tb0.3Dy0.7Fe2)(100-x)Fe-x films, where x can range from 0% to 100%. Unlike films obtained by standard nanosecond PLD, pure terfenol-D layers (x = 0) are amorphous, while the addition of iron induces the formation of Fe crystalline nanoparticles inside an amorphous nanogranular matrix of terfenol-D. The magnetic properties depend on the nanoparticle morphology and more strictly on the fraction of iron particles. In particular, it was demonstrated that the exchange interaction between hard magnetic terfenol-D nanoparticles and iron nanoparticles is active in the uPLD films, giving a cumulative magnetic response resulting from an averaging of the properties of the two component phases.