Magneto-transport studies in Gd-Fe thin films

Abstract

Tuning the perpendicular magnetic anisotropy (PMA) in magnetic thin films has been an interest for several decades owing to its potential in magnetic recording applications. For device-level applications, it is preferable to employ a single film layer with PMA instead of a multilayer to evade the complicated fabrication process. Therefore, there is a search for materials exhibiting strong PMA in a single layer. Of the several materials exhibiting PMA, rare-earth transition metal-based Gd-Fe thin films have attracted special attention from both the fundamental and technological viewpoints. Gd-Fe films exhibit tunable magnetic anisotropy that can be tailored by modifying the composition, thickness, ion-irradiation and annealing conditions, etc.[1]. Although substantial work has been carried out in understanding the magnetic anisotropy of these films, studies on magnetic transport are still elusive. In the present study, we have grown 150 nm thick Gd-Fe thin film capped with 5nm Cr on Si and Si/SiO2 substrates by electron-beam evaporation under vacuum. Films were found to be amorphous in nature due to the large difference between the atomic radius of Gd and Fe atoms and high cooling rate attained during the deposition process. Magnetization measurements and domain imaging studies indicated the anisotropy axis is tilted in between in-plane and out-of-plane direction. This inherent tilt anisotropy makes it a unique material for sensing vector fields. Magneto-transport measurement on this film showed positive magneto-resistance along both in-plane (IP) and out-of-plane (OOP) directions. This resistance change was mainly contributed by the scattering at domain walls [2].