A Study on the Magnetic Ordering in Fe$_{3}$Al and (Fe$_{0.7}$Ni$_{0.3}$)$_{3}$Al Alloy Films

The magnetic ordering in Fe$_{3}$Al and (Fe$_{0.7}$Ni$_{0.3}$)$_ {3}$Al films were investigated by Brillouin light scattering (BLS), and compared with the results using a superconducting quantum interference device (SQUID). (Fe$_{0.7}$Ni$_{0.3}$)$_{3} $Al and Fe$_{3}$Al films (100 nm thick) were deposited at room temperature and 400$^{\circ}$C on Si(100) substrates by ultrahigh-vacuum dc magnetron co-sputtering. The crystal structures were understood by x-ray diffraction in glancing- incidence mode. In order to obtain the values of the $g$-factor, the saturated magnetization and the spin-wave stiffness constant, the BLS experiments were employed. The temperature dependence of magnetization was measured at 5 - 150 K in an applied field of 3 kOe by using the SQUID. It was found that the magnetic ordering in the (Fe$_{0.7}$Ni$_{0.3}$)$_{3}$Al film, based on both the SQUID and the BLS measurements, are weaker than the Fe$_{3}$Al film.