Temperature dependence of FMR surface spin-wave mode of amorphous Fe40Ni40B20 alloys

Abstract The temperature dependence (3 to 300 K) of the FMR surface spin-wave mode on annealed ribbons of the Fe 40 Ni 40 B 20 alloy was measured at 48 GHz. Using the macroscopic FMR theory the values of the surface anisotropy constant were determined as 1.15 erg/cm 2 at 3 K decreasing to 0.6 erg/cm 2 at 293 K; the exchange-stiffness constant at 0K amounts to 169 meVa 2 .