Anisotropic magnetoresistance in FeGa films with stripe domains

M. GRANADA; L. FERNÁNDEZ; B. CANTO; M. BARTUREN; J. MILANO; S. BUSTINGORRY; M. EDDRIEF; M. MARANGOLO

Buenos Aires

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

Fe1-xGax alloys have been widely studied in the last years due to the high magnetostrictive coefficient displayed for some specific Ga concentrations, attaining a maximum for x~19%. Thin films of FeGa have also been fabricated and implemented in devices playing the role of either sensor or actuator. The structural and magnetic properties of MBE grown FeGa films have been studied [1]. Samples within some Ga concentration range and with thicknesses larger than a critical value, present a stripe domain arrangement in the remanent state, with stripes lying along the in-plane applied field direction [2]. Magnetotransport measurements are particularly sensitive to local magnetic properties, and could be an interesting tool for detecting magnetization changes due to magnetostrictive effects. In this work, we studied the magnetoresistance (MR) of Fe0.8Ga0.2 films with stripe domains. Qualitatively different curves were measured when the magnetic field was applied parallel or perpendicular to the electric current, i.e., with the electrons flowing along or across the stripe domains. Anisotropic magnetoresistance (AMR) proved to be the leading contribution to MR measured in these samples. In order to have some insight into the magnetic structure and its influence on electronic transport, we studied the temperature dependence of MR. The perpendicular MR remains roughly the same when temperature is varied, while parallel MR is strongly temperature dependent, changing sign at 250 K. We analyzed this effect in terms of a simple model of parallel or series conduction (depending on the geometry of measurement) that takes into account the resistivity modulation due to the AMR. [1] M. Eddrief et al., Phys. Rev. B 84, 161410(R) (2011). [2] M. Barturen et al., Appl. Phys. Lett. 101, 092404 (2012).