Magnetic properties and microstructure of TbxDy1−xFe2 thin films sputtered on Pt/TiO2/SiO2/Si substrate

TbxDy1−xFe2 thin films are grown on Pt/TiO2/SiO2/Si substrate by multi-target sputtering. In order to achieve the best magnetic properties, samples grown while heating the sample holder (in situ films) are compared to those prepared at room temperature followed by thermal annealing. The effect of Tb, Dy and Fe content is also examined. It is found that the magnetic properties are very sensitive to the deposition parameters. Magnetization value as high as 680 emu/cm3 with very low coercivity is achieved in a 140 nm thick film whose composition (Tb0.3Dy0.7)Fe2 corresponds to the TERFENOL-D formulation. Observation of soft ferromagnetism and high magnetization are related to crystallization of nano-grains (size 7–10 nm) as deduced from microstructure investigation by X ray diffraction and transmission electron microscopy. It is shown the possibility of growing TERFENOL-D thin films with properties suitable for observation of extrinsic magneto-electric coupling in future thin film devices combining piezoelectric and magnetostrictive materials on metallized silicon substrate.