Microstructural evolution and magnetic properties in Fe50Pd50 sputtered thin films submitted to post-deposition annealing

Abstract

Fe50Pd50 thin films (t=50nm) have been deposited on Si substrates covered with a native oxide layer by sputtering technique. As-prepared films consist of a disordered Fe–Pd A1 phase, being deposited without heating the substrate. The order–disorder transformation towards the L10-ordered tetragonal phase has been induced by post deposition annealing in vacuum (annealing temperature ranging in the interval Ta=550–625°C for 1200s). Samples microstructure has been studied by means of X-ray diffraction, SEM and AFM microscopy. Room-temperature hysteresis loops have been measured by AGFM (Alternating Gradient Field Magnetometer) in parallel and perpendicular configuration. All produced systems have been observed to display tunable microstructure and, consequently, various magnetic properties. To study the magnetic properties evolution with annealing temperature, magnetic domain patterns have been measured by MFM. In particular, the domain-period dependence on the magnetocrystalline anisotropy constant has been analyzed.