Fabrication, structural and magnetic behavior of novel one-dimensional Fe2MnGa nanostructures

Abstract

Well aligned Fe2MnGa nanowires (NWs) have been synthesized through low cost and versatile electrochemical deposition technique with constant stirring during the growth process in anodic aluminum oxide (AAO) templates. The average diameter is 50 nm and the lengths up to a few micrometers have been confirmed through morphological analysis. The NWs are found to be in body centered cubic structure with (220) preferred orientation. The magnetic behavior has been investigated at room temperature (RT) as well as at low temperatures. The dominant shape anisotropy compelled the preferable magnetization axis to be in axial direction of NWs. Angular dependence of coercivity shows coherent rotation of magnetic domain on reversal of external magnetic field due to the stronger interwire couplings. At lower temperatures, superparamagnetic contributions from very small nanoparticles in blocking state significantly improved saturation magnetization (Ms) from 0.101 to 0.205 emu and coercivity from 1354 to 1632 Oe. A mixed behavior of exchange bias has been manifested by the NWs at lower temperatures owing to the rearrangement of atoms between the interface of antiferromagnetic and ferromagnetic grains. This causes significant disturbance for pining effect resulting fluctuating exchange bias phenomenon.