Anisotropic Magnetotransport in Thin Films of Helical Antiferromagnet Fe₃Ga₄

Helical spin order derived from the relative orientation of spin moments between magnetic planes hosts fascinating effects like spin filtering, non-collinear spin texture and meta-magnetism.^{1, 2} In this study, we explore the growth and characterization of helical antiferromagnet Fe₃Ga₄ thin films, focusing on their helical antiferromagnetic ordering and its influence on anomalous magneto-transport properties. The films were grown using magnetron sputtering technique on SrTiO₃ (001) substrate and post-annealed at high temperatures. Detailed analysis of temperature and magnetic field dependent magnetoresistance, anomalous Hall effect (ρ_xy^AHE), anisotropic magnetoresistance (△ρ_xx), and planar Hall effect (ρ_xy^PHE) measurements indicate ferromagnetic phase in the temperature range T<100 K and T>300 K, whereas switching to helical antiferromagnetic ordering is observed at 100 <T<300 K. In the low temperature ferromagnetic phase, ρ_xyAHE, △ρ_xx, and ρ_xy^PHE suggest a combination of non-trivial topological texture and magnetic field dependent scattering. However, at high temperatures, the ferromagnetic phase exhibits more conventional behavior, driven by spontaneous magnetization and spin orbit coupling. Our findings provide insights into the complex interplay between magnetic ordering and electronic transport in Fe₃Ga₄ thin films, offering new perspectives for their application in spintronics technologies.