| AVS 61st International Symposium & Exhibition | |
| Thin Film | Monday Sessions |
| Session TF+PS+SE-MoM |
| Session: | Advanced PVD Methods |
| Presenter: | Colin Rementer, University of California at Los Angeles |
| Authors: | C. Rementer, University of California at Los Angeles Y. Kim, University of California at Los Angeles J.P. Chang, University of California at Los Angeles |
| Correspondent: | Click to Email |
Iron gallium boron, i.e. (Fe80Ga20)xB1-x or FeGaB, is a material of considerable interest for high frequency, multiferroic applications. Lou et al. discovered that the addition of boron to the magnetostrictive material Galfenol (Fe80Ga20 or FeGa) led to a decrease in coercivity (~1 Oe), decrease in ferromagnetic resonance (FMR) linewidth (~20 Oe) at X band, and an increase in piezomagnetic coefficient (~7 ppm/Oe). The physical properties were optimized in (Fe80Ga20)88B12 with ~100 nm thickness (Lou, J. et al. 2007). The material has been incorporated into several multiferroic systems with great success ( Lou, J. et al. 2009). It is a material of great interest for integration into various multiferroic antenna systems. To have a better understanding of the material, a more thorough study on the fundamental properties of the material at different thicknesses is needed, as well as how that thickness can affect the tunability of resonant frequency and magnetoelectric coupling in multiferroic heterostructures when incorporated with ferroelectric single crystals.
FeGaB was grown via co-sputtering of Fe80Ga20 and boron targets via DC magnetron and RF magnetron sputtering, respectively. The FeGa target was held at 60 W and the boron power was adjusted to tune the boron concentration, from 9 - 18%. FeGaB films were grown with thicknesses ranging from 30 nm – 500 nm, and a growth rate of 7 nm/min was achieved. The coercivity and saturation magnetization of the FeGaB films decreased (~10 Oe), and increased (1200 emu/cc), respectively, with decreasing thickness (30 nm). Ferromagnetic resonance (FMR) linewidth was measured at X band (9.6 GHz), and it was found that it narrowed to 140 Oe with decreasing thickness at 30 nm. Both Fe75Ga25 and Fe60Ga22B18 were shown to be magnetoelastic, having magnetostriction constants of around 30 ppm and 60 ppm, respectively. The magnetic properties of FeGaB are being optimized to the properties measure by Lou et al. to ensure the rigor of the thickness dependence study (Lou, J. et al. 2007). The effect of inducing stronger in-plane anisotropy in the FeGaB films was investigated via an in situ magnetic field applied during deposition, and post-deposited magnetic annealing is being explored as a function of thickness.