Self-organized stripe-like domains in Fe1-xGax thin films epitaxied on GaAs(001),

M. BARTUREN; M. MARANGOLO; J. MILANO; M. EDDRIEF; V. ETGENS; Y. ZHENG; M. SACCHI; S. BUSTINGORRY; A. BUTERA

Buenos Aires

Congreso; X Latin American Workshop on Magnetism, Magnetic Materials and Their Applications; 2013

One of the materials with largest magnetoelastic coupling is the iron-gallium alloy FeGa (Galfenol)[1]. Up to now, most of the research was devoted to study the FeGa in bulk form. However, in order to be integrated in nanodevices it is important to study FeGa thin films, mainly when they are epitaxially grown onto a semiconductor substrate like GaAs(001) [2].By molecular beam epitaxy (MBE) we grew a series of (001)-oriented films (30-70nm thick), with concentrations ranging from pure Fe up to x=29.4 % Ga.[2]We find a strong Ga-induced tetragonal distortion that preserves the bulk Fe in-plane lattice parameters for all Ga compositions. Supported by theoretical predictions [3], we attribute this unusual tetragonal distortion to short-range ordering of Ga-Ga pairs along the [001]-growth direction. This tetragonal structure is fully released by post-growth annealing.Here we show that the tetragonal distortion combined with the strong magnetostriction induces anout-of-plane component of the Fe1-x Gax films magnetization and particular features in hysteresis loops.MFM measurements indicate a self-organized striped pattern (period 150 nm) with rotatable anisotropy.Self organization is affected by the the film thickness and the Ga content [4].[1] A. Clark, J. Restor, M. Wun-Fogle, T. Lograsso, and D. Schlagel, IEEE Trans. Magn. 36, 3238 (2000).[2] M. Eddrief, Y. Zheng, S. Hidki, B. Rache Salles, J. Milano, V. H. Etgens, and M. Marangolo Phys. Rev.B 84 161410(R) (2011).[3] R. Wu J. Appl. Phys. 91 7358 (2002). [4] M. Barturen, B. Rache Salles, P. Schio, J. Milano, A. Butera, S. Bustingorry, C. Ramos, A. J. A. de Oliveira, M. Eddrief, E. Lacaze, F. Gendron, V. Etgens, M. Marangolo, Appl. Phys. Lett. 101 9 092404 (2012).