Investigation of Spin Pinned Effect in Ni/NiFe/Ni Trilayers Via Ferromagnetic Resonance Spectroscopy

Abstract

Recently, increasing the application frequency of devices through spin wave resonance has received widespread attention. Exciting spin waves through the spin pinning effect of the Ni film on the surface of the Ni81Fe19 film is of great significance to increase the application frequency of the device. Herein, the Ni (t nm)/Ni81Fe19 (50 nm)/Ni (t nm) multilayer films, which were fabricated by magnetron sputtering. And the micromorphology, static magnetic properties, ferromagnetic resonance (FMR) linewidth (∆H) are discussed in detail. As the Ni film thicknesses increased, the saturation magnetization (4πMs) of the trilayers decreased from 7405 to 5805 Gs. When the Ni film thickness was below 10 nm, ∆H showed an upward trend, and the ∆H slightly decreased at 15 nm Ni film thickness. When Ni film thickness was less than 10 nm, the perpendicular standing spin wave (PSSW) mode appeared, which implied a strong pinning effect. With 10 nm and 15 nm Ni film, the PSSW mode disappeared, indicating that the large grain size was not conducive to the pinning effect of the film.