Tuning the magnetic domain patterns of sputtered TbFeGa alloys

The control of the magnetic domain patterns together with their time and temperature stability are key issues for the development of new devices. Materials systems with perpendicular magnetic anisotropy (PMA) are of great interest because of their applications on patterned media for magnetic storage or in spintronic devices. Nowadays, different approaches are analyzed to reach this high magnetic anisotropy, leading to various structures such as FePt and CoPt layers, multilayers comprising magnetic transition metals (Co, Fe, CoFe) and noble metals (Pt, Pd, Au) or FeCoB layers with PMA. Some years ago, Tb-Fe alloys were greatly investigated because of their large out-of-plane anisotropy constant. In spite of this high PMA, for industrial applications it is desirable to have materials with a reduced heavy rare earth content. Some works on bulk TbFeGa alloys have focused on their magnetostrictive properties but the magnetic anisotropy of TbFeGa thin films has just started to be studied. In this work, we present our investigations on the magnetic properties of TbFeGa thin films. The alloys were obtained by the cosputtering technique using two targets with a composition of TbFe2 and Fe3Ga. Different compositions can be achieved by modifying the power in each sputtering target. Moreover, we have also observed that the magnetic anisotropy and domain patterns also depends on the type of power source used (DC or pulsed). In particular, the evaporation of TbFe2 by means of the DC source enhances the out of plane component of the magnetization being obtained an anisotropy constant of at least 1×10^6 erg/cm3 . The results indicate that this is due to the Tb enrichment of the TbFe2-based phases present in the alloys. Therefore, the magnetic domain pattern can be tailored by means of the composition and the type of power source used in each sputtering target