Magnetic and Electrical Properties of Fe90Ta10 Thin Films

Fe90Ta10 (Fe-Ta) thin films, deposited using a pulsed laser deposition (PLD) method, have been found to exhibit characteristics of a soft ferromagnetic material with very low coercivities (1-10 mT) and saturation magnetization ~ 16 105 A/m. Our temperature dependent magnetization data at several fields (0.1 – 3 T) have conclusively detected the anharmonic term in the magnon dispersion relation. Moreover, the rigid-band model for metallic alloys can predict correctly the magnetic moment of ~ 2 µB as found by us from the above magnetization data of Fe90Ta10. We have also observed an Extraordinary Hall Effect (EHE) in these films. The extrinsic quantum mechanical side-jump mechanism as well as the intrinsic mechanism (due to the Berry phase curvatures) are responsible for the EHE varying here as the square of the electrical resistivity. Thus, our interpretation of the data at every stage is backed by theoretical considerations.